RFR 9: JDK-8130877 : (process) java/lang/ProcessHandle/TreeTest test3 failure - Destroyed process.isAlive

[Roger Riggs]

Please review a testbug to correctly look for destroyed processes.

Webrev:
   http://cr.openjdk.java.net/~rriggs/webrev-isalive-8130877/

Issue:
  https://bugs.openjdk.java.net/browse/JDK-8130877

Thanks, Roger