RFR 8177932 (process) java/lang/ProcessHandle/OnExitTest.java failed with "Process A should not be alive"

[Roger Riggs]

Please review a fix for an intermittent issue with ProcessHandle.onExit.
On Solaris, the start time of a process reported through 
/proc/pid/psinfo changes to
zero when the process is exiting.  The onExit implementation incorrectly 
interpreted zero
meaning the pid had been re-used and the process was no longer alive.  
However,
ProcessHandle.isAlive considered zero to be missing information and the 
process was still alive.

Webrev:
   http://cr.openjdk.java.net/~rriggs/webrev-onexit-8177932/

Issue:
   https://bugs.openjdk.java.net/browse/JDK-8177932

Thanks, Roger