RFR 9: 8146574 (process) ProcessHandle test cleanup

[Roger Riggs]

Please review a few cleanups of the ProcessHandle tests.
  - Switch to the jdk.test.lib (from lib/testlibrary )
  - Cleanup import statements
  - Remove TEST.properties and use explicit @run testng argument in each 
test

Webrev:
     http://cr.openjdk.java.net/~rriggs/webrev-testlibrary-8146574/

Issue:
    https://bugs.openjdk.java.net/browse/JDK-8146574

Thanks, Roger