assert(!is_null(v)) failed: narrow klass value can never be zero

Stress test hit following assertion:

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (open/src/hotspot/share/oops/compressedOops.inline.hpp:84), pid=7075, tid=7175
# assert(!is_null(v)) failed: narrow klass value can never be zero
#
# JRE version: Java(TM) SE Runtime Environment (15.0+7) (fastdebug build 15-ea+7-127)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 15-ea+7-127, compiled mode, sharing, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x578b04] CompressedKlassPointers::decode_not_null(unsigned int)+0x54
#
# Core dump will be written. Default location: Core dumps may be processed with "/opt/core.sh %p" (or dumping to /opt/mach5/mesos/work_dir/slaves/6e54f4af-e606-43b0-80ce-0a482a5988b6-S253/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/c6c3eba5-a29d-4b42-88e0-76de9c0f6ad5/runs/213c59ad-9897-47a7-8c39-83deda2311fd/testoutput/test-support/jtreg_closed_test_hotspot_jtreg_applications_kitchensink_Kitchensink_java/scratch/0/core.7075)
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#

--------------- S U M M A R Y ------------

Command Line: -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:MaxRAMPercentage=6 -Xcomp -XX:+CreateCoredumpOnCrash -ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -XX:-TieredCompilation -XX:MaxRAMPercentage=50 -XX:MaxMetaspaceSize=256m -XX:+HeapDumpOnOutOfMemoryError -XX:+CrashOnOutOfMemoryError -Djava.net.preferIPv6Addresses=false -XX:+DisplayVMOutputToStderr -Xlog:gc*,gc+heap=debug:gc.log:uptime,timemillis,level,tags -XX:+DisableExplicitGC -XX:+StartAttachListener --add-exports=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang=ALL-UNNAMED --add-exports=java.xml/com.sun.org.apache.xerces.internal.parsers=ALL-UNNAMED --add-exports=java.xml/com.sun.org.apache.xerces.internal.util=ALL-UNNAMED -Djava.io.tmpdir=/opt/mach5/mesos/work_dir/slaves/6e54f4af-e606-43b0-80ce-0a482a5988b6-S253/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/c6c3eba5-a29d-4b42-88e0-76de9c0f6ad5/runs/213c59ad-9897-47a7-8c39-83deda2311fd/testoutput/test-support/jtreg_closed_test_hotspot_jtreg_applications_kitchensink_Kitchensink_java/scratch/0/java.io.tmpdir -Duser.home=/opt/mach5/mesos/work_dir/slaves/6e54f4af-e606-43b0-80ce-0a482a5988b6-S253/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/c6c3eba5-a29d-4b42-88e0-76de9c0f6ad5/runs/213c59ad-9897-47a7-8c39-83deda2311fd/testoutput/test-support/jtreg_closed_test_hotspot_jtreg_applications_kitchensink_Kitchensink_java/scratch/0/user.home -agentpath:/opt/mach5/mesos/work_dir/jib-master/install/jdk-15+7-127/linux-x64-debug.test/hotspot/jtreg/native/libJvmtiStressModule.so -XX:NativeMemoryTracking=detail applications.kitchensink.process.stress.Main /opt/mach5/mesos/work_dir/slaves/6e54f4af-e606-43b0-80ce-0a482a5988b6-S253/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/c6c3eba5-a29d-4b42-88e0-76de9c0f6ad5/runs/213c59ad-9897-47a7-8c39-83deda2311fd/testoutput/test-support/jtreg_closed_test_hotspot_jtreg_applications_kitchensink_Kitchensink_java/scratch/0/kitchensink.final.properties

Host: Intel(R) Xeon(R) Platinum 8167M CPU @ 2.00GHz, 8 cores, 58G, Oracle Linux Server release 7.6
Time: Thu Jan 16 21:26:40 2020 UTC elapsed time: 1365 seconds (0d 0h 22m 45s)

--------------- T H R E A D ---------------

Current thread (0x00007f845800c000): GCTaskThread "GC Thread#6" [stack: 0x00007f83cbbfa000,0x00007f83cbcfa000] [id=7175]

Stack: [0x00007f83cbbfa000,0x00007f83cbcfa000], sp=0x00007f83cbcf88b0, free space=1018k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x578b04] CompressedKlassPointers::decode_not_null(unsigned int)+0x54
V [libjvm.so+0xac512a] G1ParScanThreadState::copy_to_survivor_space(G1HeapRegionAttr, oop, markWord)+0x3ea
V [libjvm.so+0xaf54d0] void G1ParCopyClosure<(G1Barrier)0, (G1Mark)0>::do_oop_work<oop>(oop*)+0x100
V [libjvm.so+0xac1342] unsigned long G1OopStarChunkedList::chunks_do<oop>(ChunkedList<oop*, (MemoryType)5>*, OopClosure*) [clone .isra.7]+0x52
V [libjvm.so+0xac14d0] G1OopStarChunkedList::oops_do(OopClosure*, OopClosure*)+0x20
V [libjvm.so+0xae5560] G1ScanCollectionSetRegionClosure::do_heap_region(HeapRegion*)+0x220
V [libjvm.so+0xa59770] G1CollectionSet::iterate_part_from(HeapRegionClosure*, HeapRegionClaimer*, unsigned long, unsigned long, unsigned int, unsigned int) const [clone .part.26]+0x100
V [libjvm.so+0xa5ad57] G1CollectionSet::iterate_incremental_part_from(HeapRegionClosure*, HeapRegionClaimer*, unsigned int, unsigned int) const+0x97
V [libjvm.so+0xad3419] G1RemSet::scan_collection_set_regions(G1ParScanThreadState*, unsigned int, G1GCPhaseTimes::GCParPhases, G1GCPhaseTimes::GCParPhases, G1GCPhaseTimes::GCParPhases)+0x89
V [libjvm.so+0xa4db13] G1EvacuateRegionsBaseTask::work(unsigned int)+0x83
V [libjvm.so+0x1667284] GangWorker::run_task(WorkData)+0x84
V [libjvm.so+0x16673c8] GangWorker::loop()+0x48
V [libjvm.so+0x153f5d6] Thread::call_run()+0xf6
V [libjvm.so+0x126d76e] thread_native_entry(Thread*)+0x10e

Register to memory mapping:

RAX=0x00007f84cace7000 points into unknown readable memory: 58 00 00 00 00 00 00 00
RBX=0x0 is NULL
RCX=0x00007f84c9b04588: <offset 0x00000000016fa588> in /opt/mach5/mesos/work_dir/jib-master/install/jdk-15+7-127/linux-x64-debug.jdk/jdk-15/fastdebug/lib/server/libjvm.so at 0x00007f84c840a000
RDX=0x00007f84c9c57351: <offset 0x000000000184d351> in /opt/mach5/mesos/work_dir/jib-master/install/jdk-15+7-127/linux-x64-debug.jdk/jdk-15/fastdebug/lib/server/libjvm.so at 0x00007f84c840a000
RSP=0x00007f83cbcf88b0 points into unknown readable memory: 00 00 40 a9 00 00 00 00
RBP=0x00007f83cbcf88c0 points into unknown readable memory: 60 89 cf cb 83 7f 00 00
RSI=0x0000000000000054 is an unknown value
RDI=0x00007f84c9b045b0: <offset 0x00000000016fa5b0> in /opt/mach5/mesos/work_dir/jib-master/install/jdk-15+7-127/linux-x64-debug.jdk/jdk-15/fastdebug/lib/server/libjvm.so at 0x00007f84c840a000
R8 =0x0 is NULL
R9 =0x000000000000c3e0 is an unknown value
R10=0x000000006c63925c is an unknown value
R11=0x000df65e7a7d8411 is an unknown value
R12=0x00000001bf592e40 points into unknown readable memory: 00 00 00 00 00 00 00 00
R13=0x00007f83cbcf89b8 points into unknown readable memory: 40 2e 59 bf 01 00 00 00
R14=0x00007f84b97abf3e is at entry_point+6622 in (nmethod*)0x00007f84b97a9690
R15=0x00007f83cbcf8998 points into unknown readable memory: 40 2e 59 bf 01 00 00 00


Registers:
RAX=0x00007f84cace7000, RBX=0x0000000000000000, RCX=0x00007f84c9b04588, RDX=0x00007f84c9c57351
RSP=0x00007f83cbcf88b0, RBP=0x00007f83cbcf88c0, RSI=0x0000000000000054, RDI=0x00007f84c9b045b0
R8 =0x0000000000000000, R9 =0x000000000000c3e0, R10=0x000000006c63925c, R11=0x000df65e7a7d8411
R12=0x00000001bf592e40, R13=0x00007f83cbcf89b8, R14=0x00007f84b97abf3e, R15=0x00007f83cbcf8998
RIP=0x00007f84c8982b04, EFLAGS=0x0000000000010246, CSGSFS=0x002b000000000033, ERR=0x0000000000000006
  TRAPNO=0x000000000000000e

Top of Stack: (sp=0x00007f83cbcf88b0)
0x00007f83cbcf88b0: 00000000a9400000 00007f846c056750
0x00007f83cbcf88c0: 00007f83cbcf8960 00007f84c8ecf12a
0x00007f83cbcf88d0: 0000000000000040 00007f84c4094fa0
0x00007f83cbcf88e0: 00007f83cbcf8960 00007f83cbcf89b0

Instructions: (pc=0x00007f84c8982b04)
0x00007f84c8982a04: 53 ff ff ff 0f 1f 84 00 00 00 00 00 48 89 df e8
0x00007f84c8982a14: 48 f0 e1 00 e9 1e ff ff ff 0f 1f 00 48 39 f2 0f
0x00007f84c8982a24: 84 48 ff ff ff 48 8d 05 28 dc 63 01 48 8d 3d 81
0x00007f84c8982a34: 11 18 01 48 8d 0d 3c 46 2d 01 be 8b 00 00 00 48
0x00007f84c8982a44: 8d 15 d6 11 18 01 48 8b 00 c6 00 58 31 c0 e8 09
0x00007f84c8982a54: 3b 36 00 e8 94 c6 ce 00 48 8b 7b 08 48 8b 43 10
0x00007f84c8982a64: e9 08 ff ff ff 0f 1f 80 00 00 00 00 48 8d 05 e1
0x00007f84c8982a74: db 63 01 48 8d 15 12 11 18 01 48 8d 0d dd 45 2d
0x00007f84c8982a84: 01 be 96 00 00 00 48 8d 3d 27 11 18 01 48 8b 00
0x00007f84c8982a94: c6 00 58 31 c0 e8 c2 3a 36 00 e8 4d c6 ce 00 48
0x00007f84c8982aa4: 8b 53 08 8b 42 38 e9 76 fe ff ff 90 55 48 89 e5
0x00007f84c8982ab4: 53 89 fb 48 83 ec 08 85 db 74 21 48 8d 05 6a db
0x00007f84c8982ac4: 63 01 8b 48 08 48 d3 e3 48 03 18 f6 c3 07 75 44
0x00007f84c8982ad4: 48 83 c4 08 48 89 d8 5b 5d c3 66 90 48 8d 05 71
0x00007f84c8982ae4: db 63 01 48 8d 0d 9a 1a 18 01 48 8d 15 5c 48 2d
0x00007f84c8982af4: 01 be 54 00 00 00 48 8d 3d af 1a 18 01 48 8b 00
0x00007f84c8982b04: c6 00 58 31 c0 e8 52 3a 36 00 e8 dd c5 ce 00 eb
0x00007f84c8982b14: aa 0f 1f 00 48 8d 05 39 db 63 01 49 89 d8 48 8d
0x00007f84c8982b24: 0d 43 48 2d 01 48 8d 15 b8 1a 18 01 be 56 00 00
0x00007f84c8982b34: 00 48 8d 3d 74 1a 18 01 48 8b 00 c6 00 58 31 c0
0x00007f84c8982b44: e8 17 3a 36 00 e8 a2 c5 ce 00 48 83 c4 08 48 89
0x00007f84c8982b54: d8 5b 5d c3 0f 1f 84 00 00 00 00 00 55 48 89 e5
0x00007f84c8982b64: 41 57 41 56 41 55 41 54 53 48 83 ec 78 48 8d 1d
0x00007f84c8982b74: 52 3d 6e 01 48 89 7d 88 80 3b 00 75 67 48 8b 45
0x00007f84c8982b84: 88 48 89 45 a8 48 8d 05 18 e0 5e 01 48 89 45 b0
0x00007f84c8982b94: 48 8b 45 a8 48 89 45 b8 48 c7 45 c0 00 00 00 00
0x00007f84c8982ba4: 48 8b 45 b8 45 31 e4 48 89 45 90 48 8b 45 90 48
0x00007f84c8982bb4: 89 45 98 48 8b 45 98 48 89 45 a0 48 8b 45 a0 48
0x00007f84c8982bc4: 89 45 a8 48 8b 45 a8 49 01 c4 4d 8b 24 24 48 83
0x00007f84c8982bd4: c4 78 4c 89 e0 5b 41 5c 41 5d 41 5e 41 5f 5d c3
0x00007f84c8982be4: 0f 1f 40 00 48 8d 45 88 48 89 c7 48 89 85 70 ff
0x00007f84c8982bf4: ff ff e8 e5 ff cd 00 48 8b 45 88 80 3b 00 48 89