RFR 8181080/10, Refactor several sun/net shell tests to plain java tests

[Felix Yang]

Hi there,

    please review the patch convert several sun/net shell tests to 
plain java tests.

Bug:

    https://bugs.openjdk.java.net/browse/JDK-8181080

Webrev:

    http://cr.openjdk.java.net/~xiaofeya/8181080/webrev.00/

Thanks,

Felix