jvmti/StopThread/stopthrd007 failed with "NoClassDefFoundError: Could not initialize class jdk.internal.misc.VirtualThreads"

The following test failed in the JDK21 CI:

vmTestbase/nsk/jvmti/StopThread/stopthrd007/TestDescription.java

Here's a snippet from the log file:

#section:main
----------messages:(8/397)----------
command: main -agentlib:stopthrd007=-waittime=5 nsk.jvmti.StopThread.stopthrd007
reason: User specified action: run main/othervm/native -agentlib:stopthrd007=-waittime=5 nsk.jvmti.StopThread.stopthrd007
started: Fri May 19 03:02:45 UTC 2023
Mode: othervm [/othervm specified]
Timeout information:
--- Timeout information end.
finished: Fri May 19 03:11:49 UTC 2023
elapsed time (seconds): 544.51
----------configuration:(0/0)----------
----------System.out:(1/26)----------
Timeout refired 480 times
----------System.err:(11/1002)----------
Exception in thread "DebuggeeWaitingThread" Exception in thread "DebuggeeSleepingThread" Exception in thread "DebuggeeRunningThread" java.lang.ThreadDeath
java.lang.NoClassDefFoundError: Could not initialize class jdk.internal.misc.VirtualThreads
at java.base/java.util.concurrent.locks.LockSupport.unpark(LockSupport.java:179)
at java.base/java.util.concurrent.locks.AbstractQueuedSynchronizer.signalNext(AbstractQueuedSynchronizer.java:645)
at java.base/java.util.concurrent.locks.AbstractQueuedSynchronizer.release(AbstractQueuedSynchronizer.java:1060)
at java.base/java.util.concurrent.locks.ReentrantLock.unlock(ReentrantLock.java:494)
at nsk.share.Wicket.unlock(Wicket.java:226)
at nsk.jvmti.StopThread.stopthrd007ThreadRunning.run(stopthrd007.java:195)
Caused by: java.lang.ExceptionInInitializerError: Exception java.lang.ThreadDeath [in thread "DebuggeeRunningThread"]

Exception: java.lang.NoClassDefFoundError thrown from the UncaughtExceptionHandler in thread "DebuggeeRunningThread"
----------rerun:(42/8469)*----------