----------System.out:(17/508)----------
Agent init
Main: prepareAgent started
Main: prepareAgent finished

Main #A: method A() must be blocked on entering a synchronized statement
TestTask.run: started
TestTask.A: started

Main #A.1: unsuspended
Main: stopThread: StopThread returned code: JVMTI_ERROR_THREAD_NOT_SUSPENDED (13)
Main #A.1: got expected THREAD_NOT_SUSPENDED

Main #A.2: suspended
Main: suspendThread
Main: stopThread: StopThread returned code: JVMTI_ERROR_NONE (0)

FAILED: Main #A.2: expected JVMTI_ERROR_OPAQUE_FRAME instead of: 0
----------System.err:(13/725)----------
java.lang.RuntimeException: StopThreadTest failed!
at StopThreadTest.throwFailed(StopThreadTest.java:89)
at StopThreadTest.run(StopThreadTest.java:134)
at StopThreadTest.main(StopThreadTest.java:94)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
at java.base/java.lang.Thread.run(Thread.java:1447)

This appears to be what was expected prior to the fix for JDK-8307968