RFR 8156504/9, java/net/URLPermission/nstest/lookup.sh fails intermittently

[Felix Yang]

Hi there,

     please review the following patch for an intermittent failing test. 
Converted it into plain java test and avoid free port anti-pattern.

Bug:

     https://bugs.openjdk.java.net/browse/JDK-8156504

Webrev:

     http://cr.openjdk.java.net/~xiaofeya/8156504/webrev.00/

Thanks,

Felix