RFR 8050402: Tests to check for use of policy files

[Amanda Jiang]

Hi,

Please review a new test which checks Policy is extensible with user 
defined permissions.

Bug: https://bugs.openjdk.java.net/browse/JDK-8050402
Webrev: http://cr.openjdk.java.net/~amjiang/8050402/webrev.01/

Thanks,
Amanda