RFR: 8006534 CLONE - TestLibrary.getUnusedRandomPort() fails intermittently-doesn't retry enough times

[Jim Gish]

Please review 
http://cr.openjdk.java.net/~jgish/Bug8006534-getUnusedRandomPort-retry-more/ 
<http://cr.openjdk.java.net/%7Ejgish/Bug8006534-getUnusedRandomPort-retry-more/>

TestLibrary.getUnusedPort() attempts to retry getting an ephemeral port 
10 times, which is the current number of ports in the reserved port 
range.  Debugging code added a few weeks back has revealed that 
intermittent failures in tests using this method are caused when the 
underlying socket code first returns the first number in the reserved 
port range.  Subsequent retries result in incrementing the port number 
by one until reaching the max reserved port number, which just happens 
to correspond to the 10th attempt, and the code then quits trying.

The proposed fix (one of many possible alternatives, of course) simply 
retries for twice the number of ports in the range.

Thanks,
    Jim

-- 
Jim Gish | Consulting Member of Technical Staff | +1.781.442.0304
Oracle Java Platform Group | Core Libraries Team
35 Network Drive
Burlington, MA 01803
jim.gish at oracle.com