SEGV in trim_queue_to_threshold

Test: jdk/internal/shellsupport/doc/JavadocHelperTest.java
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00007f7a24f01df1, pid=30772, tid=31016
#
# JRE version: OpenJDK Runtime Environment (18.0+14) (build 18-ea+14-704)
# Java VM: OpenJDK 64-Bit Server VM (18-ea+14-704, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x6d7df1] G1ParScanThreadState::trim_queue_to_threshold(unsigned int)+0x19b1

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

Current thread (0x00007f79e8007890): GCTaskThread "GC Thread#1" [stack: 0x00007f79ee462000,0x00007f79ee562000] [id=31016]

Stack: [0x00007f79ee462000,0x00007f79ee562000], sp=0x00007f79ee560a70, free space=1018k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x6d7df1] G1ParScanThreadState::trim_queue_to_threshold(unsigned int)+0x19b1
V [libjvm.so+0x6f46ea] G1ScanHRForRegionClosure::scan_heap_roots(HeapRegion*)+0x53a
V [libjvm.so+0x6eaec7] G1RemSet::scan_heap_roots(G1ParScanThreadState*, unsigned int, G1GCPhaseTimes::GCParPhases, G1GCPhaseTimes::GCParPhases, bool)+0x1a7
V [libjvm.so+0x69282b] G1EvacuateRegionsTask::scan_roots(G1ParScanThreadState*, unsigned int)+0x4b
V [libjvm.so+0x692f03] G1EvacuateRegionsBaseTask::work(unsigned int)+0x83
V [libjvm.so+0xdecbff] GangWorker::loop()+0x5f
V [libjvm.so+0xdecc5f]
V [libjvm.so+0xd413d0] Thread::call_run()+0xc0
V [libjvm.so+0xba7591] thread_native_entry(Thread*)+0xe1

R12=0x00000000fdb7aa39 is pointing into object: java.lang.ref.ReferenceQueue
{0x00000000fdb7aa20} - klass: 'java/lang/ref/ReferenceQueue'
 - ---- fields (total size 4 words):
 - private final 'lock' 'Ljava/lang/ref/ReferenceQueue$Lock;' @12 a 'java/lang/ref/ReferenceQueue$Lock'{0x00000000fdb7aa40} (fdb7aa40)
 - private 'queueLength' 'J' @16 7 (7 0)
 - private volatile 'head' 'Ljava/lang/ref/Reference;' @24
[error occurred during error reporting (printing register info), id 0xb, SIGSEGV (0xb) at pc=0x00007f7a253badf4]