Three tests under sun/management/jmxremote/startstop/ failed intermittently on ppc64le with jdk16

Three tests under sun/management/jmxremote/startstop/ failed intermittently on ppc64le with jdk16

sun/management/jmxremote/startstop/JMXStartStopTest.java.JMXStartStopTest
sun/management/jmxremote/startstop/JMXStatusPerfCountersTest.java.JMXStatusPerfCountersTest
sun/management/jmxremote/startstop/JMXStatusTest.java.JMXStatusTest

Reran 100 times.
JMXStartStopTest.java 3/100 failed
JMXStatusPerfCountersTest.java 3-4/100 failed
JMXStatusTest.java 1-2/100 failed

https://ci.adoptopenjdk.net/view/work-in-progress/job/grinder_sandbox_new/234/#showFailuresLink

https://github.com/adoptium/adoptium/issues/63#issuecomment-895311761

Error message :

```
1. Time out or . The root reason is jdk.internal.agent.AgentConfigurationError: java.rmi.server.ExportException: Port already in use: 55846; nested exception is: [TestApp{test_11}] java.net.BindException: Address already in use
2. Execution failed: 'main' threw exception: java.lang.Exception: failures: 1 , 19:59:31 [jcmd] java.lang.RuntimeException: Invalid agent state: Agent already started 19:59:31 java.lang.Exception: failures: 1 19:59:31 at com.sun.javatest.regtest.agent.TestNGRunner.main(TestNGRunner.java:96)
```

Start with sun/management/jmxremote/startstop/JMXStartStopTest.java, JMXStatusPerfCountersTest.java, and JMXStatusTest.java, then review the reported ppc64le and JDK 16 failures in the linked grinder results. Reproduce the intermittent port-in-use and invalid-agent-state errors; the issue does not specify a proposed fix or explicit completion condition.

Written by the indexing model from the issue text.