The log shows

----------System.out:(1/466)----------
OK - got expected exception: java.lang.IllegalAccessError: class HostNoNestMember tried to access private field HostNoNestMember$Member.value (HostNoNestMember and HostNoNestMember$Member are in unnamed module of loader java.net.URLClassLoader @101df177), (Type HostNoNestMember$Member (loader: java.net.URLClassLoader @101df177) is not a nest member of type HostNoNestMember (loader: java.net.URLClassLoader @101df177): current type is not listed as a nest member)
----------System.err:(10/538)----------
java.lang.Error: Unexpected interrupt
at TestNestHostErrorWithMultiThread.main(TestNestHostErrorWithMultiThread.java:63)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:335)
at java.base/java.lang.Thread.run(Thread.java:1516)

There is only one printout of "OK ..." where there should be two. Investigation by [~jpai] suggests that jtreg will interrupt threads if it detects an uncaught exception from a test thread. Unfortunately this uncaught exception does not appear to be being logged to the test log.