Test gc/g1/TestShrinkAuxiliaryData10.java fails with SEGV during heap verification. Failure is highly intermittent. Only seen once during hundreds of runs.

Find full hs_err in attachement.
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00007f6403f4dd05, pid=6971, tid=7003
#
# JRE version: Java(TM) SE Runtime Environment (11.0+20) (fastdebug build 11-ea+20)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 11-ea+20, mixed mode, tiered, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x9f4d05] CodeCache::blobs_do(CodeBlobClosure*)+0xc5
#
# Core dump will be written. Default location: Core dumps may be processed with "/usr/libexec/abrt-hook-ccpp %s %c %p %u %g %t e %P %I" (or dumping to /scratch/lmesnik/ws/sbr/20/linux-x64/results/run_233/tier1/JTwork/hotspot_jtreg_0/gc/g1/TestShrinkAuxiliaryData10/core.6971)
#
# If you would like to submit a bug report, please visit:
# http://bugreport.java.com/bugreport/crash.jsp
#

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

Command Line: -XX:MaxRAMPercentage=2 -XX:NewSize=16m -XX:MinHeapFreeRatio=10 -XX:MaxHeapFreeRatio=11 -XX:+UseG1GC -XX:G1HeapRegionSize=1048576 -XX:-ExplicitGCInvokesConcurrent -Xlog:gc=debug -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI --add-exports=java.base/jdk.internal.misc=ALL-UNNAMED -Xbootclasspath/a:. -XX:G1ConcRSLogCacheSize=10 -XX:ObjectAlignmentInBytes=16 TestShrinkAuxiliaryData$ShrinkAuxiliaryDataTest

Host: scaaa755.us.oracle.com, Intel(R) Xeon(R) CPU E5-2690 0 @ 2.90GHz, 32 cores, 251G, Oracle Linux Server release 7.3
Time: Sat Jul 7 06:18:29 2018 PDT elapsed time: 2 seconds (0d 0h 0m 2s)

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

Current thread (0x00007f63fc9c4800): VMThread "VM Thread" [stack: 0x00007f63d4bf5000,0x00007f63d4cf5000] [id=7003]

Stack: [0x00007f63d4bf5000,0x00007f63d4cf5000], sp=0x00007f63d4cf3810, 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+0x9f4d05] CodeCache::blobs_do(CodeBlobClosure*)+0xc5
V [libjvm.so+0xd88d9a] G1RootProcessor::process_all_roots(OopClosure*, CLDClosure*, CodeBlobClosure*, bool)+0xca
V [libjvm.so+0xd33b33] G1HeapVerifier::verify(VerifyOption)+0x1a3
V [libjvm.so+0x17fb04b] Universe::verify(VerifyOption, char const*)+0x21b
V [libjvm.so+0x18b9b7c] VMThread::run()+0x1bc
V [libjvm.so+0x14c7a50] thread_native_entry(Thread*)+0x100