RFR 8164518: JShell: Add failover case of explicitly listening to "localhost"

[Robert Field]

Little update --
   * Slightly more general API
   * Broader testing

Please review...

Bug:
     https://bugs.openjdk.java.net/browse/JDK-8164518

Webrev:
     http://cr.openjdk.java.net/~rfield/8164518v1.webrev/

Specdiff:
http://cr.openjdk.java.net/~rfield/8164518v1.specdiff/jdk/jshell/execution/JDIDefaultExecutionControl.html
http://cr.openjdk.java.net/~rfield/8164518v1.specdiff/jdk/jshell/execution/JDIInitiator.html

API:
http://cr.openjdk.java.net/~rfield/8164518v1.jshellAPI/jdk/jshell/execution/package-summary.html

Thanks,
Robert