RFR 10 8183019: Diagnostics for onExitTest

[Roger Riggs]

Please review adding diagnostics for java.lang.ProcessHandle.OnExitTest 
[1];
on Solaris it intermittently detects a process is alive when it should 
be dead.
So far, I have not been able to reproduce it.
Also, removes unnecessary test tags.

Webrev:
   http://cr.openjdk.java.net/~rriggs/webrev-onexit-8183019/

Thanks, Roger

[1] https://bugs.openjdk.java.net/browse/JDK-8177932