The following test failed in my nightly auto-build-and-test run
on my M1 MacMini:

compiler/unsafe/SunMiscUnsafeAccessTestChar.java

Here's a snippet from the log file:

#section:testng
----------messages:(5/363)----------
command: testng -Diters=20000 compiler.unsafe.SunMiscUnsafeAccessTestChar
reason: User specified action: run testng/othervm -Diters=20000 compiler.unsafe.SunMiscUnsafeAccessTestChar
Mode: othervm [/othervm specified]
Additional options from @modules: --add-modules jdk.unsupported --add-exports jdk.unsupported/sun.misc=ALL-UNNAMED
elapsed time (seconds): 0.705
----------configuration:(4/105)----------
Boot Layer
  add modules: jdk.unsupported
  add exports: jdk.unsupported/sun.misc ALL-UNNAMED

----------System.out:(0/0)----------
----------System.err:(29/1736)----------
java.lang.NoClassDefFoundError: ororororororororo
        at org.testng.TestRunner.initMethods(TestRunner.java:435)
        at org.testng.TestRunner.init(TestRunner.java:336)
        at org.testng.TestRunner.init(TestRunner.java:289)
        at org.testng.TestRunner.<init>(TestRunner.java:180)
        at org.testng.SuiteRunner$DefaultTestRunnerFactory.newTestRunner(SuiteRunner.java:613)
        at org.testng.SuiteRunner.init(SuiteRunner.java:178)
        at org.testng.SuiteRunner.<init>(SuiteRunner.java:112)
        at org.testng.TestNG.createSuiteRunner(TestNG.java:1306)
        at org.testng.TestNG.createSuiteRunners(TestNG.java:1282)
        at org.testng.TestNG.runSuitesLocally(TestNG.java:1131)
        at org.testng.TestNG.runSuites(TestNG.java:1069)
        at org.testng.TestNG.run(TestNG.java:1037)
        at com.sun.javatest.regtest.agent.TestNGRunner.main(TestNGRunner.java:94)
        at com.sun.javatest.regtest.agent.TestNGRunner.main(TestNGRunner.java:54)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
        at java.base/java.lang.reflect.Method.invoke(Method.java:577)
        at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
        at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: java.lang.ClassNotFoundException: ororororororororo
        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
        ... 18 more

JavaTest Message: Test threw exception: java.lang.NoClassDefFoundError: ororororororororo
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.NoClassDefFoundError: ororororororororo
----------rerun:(33/5269)*----------


This failing test run is the FOURTH subtest:

 * @run testng/othervm -Diters=100 -Xint compiler.unsafe.SunMiscUnsafeAccessTestChar
 * @run testng/othervm -Diters=20000 -XX:TieredStopAtLevel=1 compiler.unsafe.SunMiscUnsafeAccessTestChar
 * @run testng/othervm -Diters=20000 -XX:-TieredCompilation compiler.unsafe.SunMiscUnsafeAccessTestChar
 * @run testng/othervm -Diters=20000 compiler.unsafe.SunMiscUnsafeAccessTestChar

It seems strange to get:

    java.lang.NoClassDefFoundError: ororororororororo

on the FOURTH invocation of the same test.