RFR 8005226: TEST_BUG: java/rmi/transport/pinClientSocketFactory/PinClientSocketFactory.java fails intermittently

[Chris Hegarty]

This is a small, test only, review request to fix an intermittently 
failing test.

There is an inherent race, and possible failure, following the 
getUnusedRandomPort pattern. This test can be modified to use a custom 
socket factory, supporting listening on an ephemeral port, without 
changing the behavior of the test.

http://cr.openjdk.java.net/~chegar/8005226/webrev.00/webrev/

-Chris.