Our internal CI has detected stress/collect-continuously-should-not-wake-concurrent-collector-after-prevent-collection-is-called.js crashing twice now: first on Wednesday last week, then again this morning. I've never seen this test crashing before, so I think a recent change is trunk is likely the culprit:

Running stress/collect-continuously-should-not-wake-concurrent-collector-after-prevent-collection-is-called.js.default
stress/collect-continuously-should-not-wake-concurrent-collector-after-prevent-collection-is-called.js.default: test_script_5107: line 2: 1377376 Segmentation fault      (core dumped) ( "$@" /home/jenkins/workspace/WebKit-JSC/label/aarch64/WebKitBuild/Release/bin/jsc --useFTLJIT\=false --useFunctionDotArguments\=true --validateExceptionChecks\=true --useDollarVM\=true --maxPerThreadStackUsage\=1572864 --useFTLJIT\=true --maxPerThreadStackUsage\=1572864 --forceMiniVMMode\=1 --stealEmptyBlocksFromOtherAllocators\=0 --collectContinuously\=1 --watchdog\=3000 --watchdog-exception-ok collect-continuously-should-not-wake-concurrent-collector-after-prevent-collection-is-called.js )
stress/collect-continuously-should-not-wake-concurrent-collector-after-prevent-collection-is-called.js.default: ERROR: Unexpected exit code: 139
FAIL: stress/collect-continuously-should-not-wake-concurrent-collector-after-prevent-collection-is-called.js.default

Since we can't get a backtrace from the CI, it is effectively impossible to fix unless somebody can reproduce it, but I'm reporting this anyway just in case somebody manages to reproduce it in the future.