The follow test failed due to "Windbg Error: WaitForEvent failed!":

serviceability/sa/TestClhsdbJstackLock.java

Here's a snippet from the log file:

----------System.out:(8/389)----------
Starting TestClhsdbJstackLock test
Started LingeredAppWithLock with pid 12032
Starting clhsdb against 12032
[2019-08-31T08:51:00.794457900Z] Gathering output for process 37924
[2019-08-31T08:51:02.851273Z] Waiting for completion for process 37924
[2019-08-31T08:51:02.851273Z] Waiting for completion finished for process 37924
hsdb> Command not valid until attached to a VM
hsdb> 
----------System.err:(49/3524)*----------
Command line: ['c:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-14+13-430\\windows-x64-debug.jdk\\jdk-14\\fastdebug/bin/java' '-XX:MaxRAMPercentage=3' '-cp' 'T:\\testoutput\\test-support\\jtreg_open_test_hotspot_jtreg_hotspot_serviceability\\classes\\0\\serviceability\\sa\\TestClhsdbJstackLock.d;T:\\testoutput\\test-support\\jtreg_open_test_hotspot_jtreg_hotspot_serviceability\\classes\\0\\test\\lib' 'LingeredAppWithLock' 'a21f509f-878c-48f4-b22c-acf50a303b76.lck' ]
Attaching to process 12032, please wait...
Unable to connect to process ID 12032:

Windbg Error: WaitForEvent failed!
sun.jvm.hotspot.debugger.DebuggerException: Windbg Error: WaitForEvent failed!
	at jdk.hotspot.agent/sun.jvm.hotspot.debugger.windbg.WindbgDebuggerLocal.attach0(Native Method)
	at jdk.hotspot.agent/sun.jvm.hotspot.debugger.windbg.WindbgDebuggerLocal.attach(WindbgDebuggerLocal.java:148)
	at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.attachDebugger(HotSpotAgent.java:672)
	at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.setupDebuggerWin32(HotSpotAgent.java:568)
	at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.setupDebugger(HotSpotAgent.java:336)
	at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:305)
	at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:141)
	at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.attachDebugger(CLHSDB.java:180)
	at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.run(CLHSDB.java:61)
	at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.main(CLHSDB.java:40)
	at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runCLHSDB(SALauncher.java:270)
	at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:406)
 stdout: [ Command not valid until attached to a VM
];
 stderr: [ Command not valid until attached to a VM
]
 exitValue = -1

 LingeredApp stdout: [];
 LingeredApp stderr: []
 LingeredApp exitValue = 0
java.lang.RuntimeException: Test ERROR java.lang.RuntimeException: '^\\s+- locked <0x[0-9a-f]+> \\(a java\\.lang\\.Class for LingeredAppWithLock\\)$' missing from stdout/stderr 

	at TestClhsdbJstackLock.main(TestClhsdbJstackLock.java:68)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:564)
	at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
	at java.base/java.lang.Thread.run(Thread.java:830)
Caused by: java.lang.RuntimeException: '^\\s+- locked <0x[0-9a-f]+> \\(a java\\.lang\\.Class for LingeredAppWithLock\\)$' missing from stdout/stderr 

	at jdk.test.lib.process.OutputAnalyzer.shouldMatch(OutputAnalyzer.java:306)
	at ClhsdbLauncher.runCmd(ClhsdbLauncher.java:148)
	at ClhsdbLauncher.run(ClhsdbLauncher.java:196)
	at TestClhsdbJstackLock.main(TestClhsdbJstackLock.java:64)
	... 6 more

JavaTest Message: Test threw exception: java.lang.RuntimeException: Test ERROR java.lang.RuntimeException: '^\\s+- locked <0x[0-9a-f]+> \\(a java\\.lang\\.Class for LingeredAppWithLock\\)$' missing from stdout/stderr 

JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.RuntimeException: Test ERROR java.lang.RuntimeException: '^\\s+- locked <0x[0-9a-f]+> \\(a java\\.lang\\.Class for LingeredAppWithLock\\)$' missing from stdout/stderr
----------rerun:(37/5009)*----------