RFR 8181413/10, Refactor test/sun/net/www/protocol/jar/jarbug/run.sh to plain java tests

[Felix Yang]

Hi there,

     please review the patch to covert a shell test to a plain java 
test, and simplify a few of  unnecessary test logic.

Bug:

     https://bugs.openjdk.java.net/browse/JDK-8181413

Webrev:

     http://cr.openjdk.java.net/~xiaofeya/8181413/webrev.00/

Thanks,

Felix