RFR: 8209595: MonitorVmStartTerminate.java timed out

[Kevin Walls]

>From studying test failures, it looks like the way the test identifies its related processes is failing.
It checks the mainArgs of a process by attaching, and looks like it occasionally misses getting a valid match.  The hasMainArgs method ignores exceptions as it is expecting some exceptions: it is going to test unrelated java process which happen to start.

It should retry this main args check on failure, but not too many times to be a burden on other valid unrelated processes, and should also log the PIDs that have an issue so we can see if this is part of any future failure.

Other small logging changes so we can see more easily the progress through the test.

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Commit messages:
 - Comment, and move takeNap() sleep method.
 - 8209595: MonitorVmStartTerminate.java timed out

Changes: https://git.openjdk.org/jdk/pull/16077/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16077&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8209595
  Stats: 43 lines in 1 file changed: 23 ins; 9 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/16077.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16077/head:pull/16077

PR: https://git.openjdk.org/jdk/pull/16077