This test failed once in the CI, on linux-64. The test was run hundreds of times on all platforms before pushing (on Oct 27) but the test may require more bedding into time. The failure in the CI was:

----------System.out:(14/278)----------
openAndClose ...
openAndClose ...
openAndUnref ...
openRegisterAndClose ...
openRegisterAndUnref ...
openAndClose ...
openAndClose ...
openAndUnref ...
openRegisterAndClose ...
openRegisterAndUnref ...
openAndClose ...
openAndClose ...
openAndUnref ...
openRegisterAndClose ...
----------System.err:(15/861)----------
java.lang.RuntimeException: actual=13, expected=12
at Unref.assertEquals(Unref.java:167)
at Unref.test(Unref.java:80)
at Unref.main(Unref.java:61)
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)

JavaTest Message: Test threw exception: java.lang.RuntimeException: actual=13, expected=12
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.RuntimeException: actual=13, expected=12