The log shows:

[19:13:43.534] # ERROR: Unexpected exception: com.sun.jdi.ObjectCollectedException
The following stacktrace is for failure analysis.
nsk.share.TestFailure: Unexpected exception: com.sun.jdi.ObjectCollectedException
at nsk.share.Log.logExceptionForFailureAnalysis(Log.java:309)
at nsk.share.Log.complain(Log.java:280)
at nsk.jdi.ObjectReference.referringObjects.referringObjects003.referringObjects003.checkThreadGroupDisableCollection(referringObjects003.java:233)
at nsk.jdi.ObjectReference.referringObjects.referringObjects003.referringObjects003.doTest(referringObjects003.java:205)
at nsk.share.jdi.SerialExecutionDebugger.executeTests(SerialExecutionDebugger.java:298)
at nsk.share.jdi.SerialExecutionDebugger.doTest(SerialExecutionDebugger.java:237)
at nsk.share.jdi.TestDebuggerType2.runIt(TestDebuggerType2.java:214)
at nsk.share.jdi.SerialExecutionDebugger.main(SerialExecutionDebugger.java:65)
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$MainTask.run(MainWrapper.java:138)
at java.base/java.lang.Thread.run(Thread.java:1474)
com.sun.jdi.ObjectCollectedException
at jdk.jdi/com.sun.tools.jdi.JDWPException.toJDIException(JDWPException.java:56)
at jdk.jdi/com.sun.tools.jdi.ObjectReferenceImpl.referringObjects(ObjectReferenceImpl.java:556)
at nsk.jdi.ObjectReference.referringObjects.referringObjects003.referringObjects003.checkThreadGroupDisableCollection(referringObjects003.java:231)
at nsk.jdi.ObjectReference.referringObjects.referringObjects003.referringObjects003.doTest(referringObjects003.java:205)
at nsk.share.jdi.SerialExecutionDebugger.executeTests(SerialExecutionDebugger.java:298)
at nsk.share.jdi.SerialExecutionDebugger.doTest(SerialExecutionDebugger.java:237)
at nsk.share.jdi.TestDebuggerType2.runIt(TestDebuggerType2.java:214)
at nsk.share.jdi.SerialExecutionDebugger.main(SerialExecutionDebugger.java:65)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
at java.base/java.lang.Thread.run(Thread.java:1474)
[19:13:43.550] Debugger nsk.jdi.ObjectReference.referringObjects.referringObjects003.referringObjects003@6fd1553b finished successfully
[19:13:43.550] debugee.stderr> [19:13:43.550] Debuggee: received the command: quit
[19:13:43.550] debugee.stderr> [19:13:43.550] Debuggee: exiting
[19:13:43.558] debugee.stderr> [19:13:43.558] Debuggee nsk.jdi.ObjectReference.referringObjects.referringObjects003.referringObjects003a@1622988d finished successfully
[19:13:43.558] debugee.stderr> [19:13:43.558] Debuggee nsk.share.jdi.SerialExecutionDebuggee : sending the command: ready
[19:13:43.558] debugee.stderr> [19:13:43.558] Debuggee: received the command: COMMAND_CLEAR_DEBUGGEE
[19:13:44.565] debugee.stderr> [19:13:44.565] Debuggee nsk.share.jdi.SerialExecutionDebuggee : sending the command: ready
[19:13:44.565] Execute debugger: nsk.jdi.ObjectReference.referringObjects.referringObjects004.referringObjects004@3c058a45
[19:13:44.565] debugee.stderr> [19:13:44.565] Debuggee: received the command: COMMAND_EXECUTE_DEBUGGEE:nsk.share.jdi.HeapwalkingDebuggee
[19:13:44.565] debugee.stderr> [19:13:44.565] Debuggee nsk.share.jdi.HeapwalkingDebuggee : sending the command: ready
[19:13:44.582] debugee.stderr> [19:13:44.582] Debuggee: received the command: createInstances:nsk.share.jdi.TestClass1:1:100000:STRONG
[19:13:44.613] debugee.stderr> [19:13:44.613] Debuggee nsk.share.jdi.HeapwalkingDebuggee : sending the command: ready
Timeout signalled after 120 seconds
[19:15:55.281] Debugger nsk.jdi.ObjectReference.referringObjects.referringObjects004.referringObjects004@3c058a45 finished successfully
[19:15:55.281] debugee.stderr> [19:15:55.281] Debuggee: received the command: quit
[19:15:55.281] debugee.stderr> [19:15:55.281] Debuggee: exiting
[19:15:55.281] debugee.stderr> [19:15:55.281] Debuggee nsk.share.jdi.HeapwalkingDebuggee@59630f32 finished successfully
[19:15:55.281] debugee.stderr> [19:15:55.281] Debuggee nsk.share.jdi.SerialExecutionDebuggee : sending the command: ready
[19:15:55.281] debugee.stderr> [19:15:55.281] Debuggee: received the command: COMMAND_CLEAR_DEBUGGEE
[19:15:56.294] debugee.stderr> [19:15:56.294] Debuggee nsk.share.jdi.SerialExecutionDebuggee : sending the command: ready
[19:15:56.304] WARNING: stop test execution because of timeout (max execution time for single test: 131729, time left: 0)
[19:15:56.304] debugee.stderr> [19:15:56.304] Debuggee: received the command: quit
[19:15:56.304] debugee.stderr> [19:15:56.304] Debuggee: exiting
[19:15:58.668] Debuggee's process finished with status: 95
[19:15:58.668] TEST PASSED

So we have an error reported, then a timeut reported, but the test claims to have passed!

The timeout is likely due to concurrent activity on the test machine.