RFR: 8072692: Improve performance of SecurityManager.checkPackageAccess

[Sean Mullan]

This is the sixth in a series of fixes for JEP 232 (Improve Secure 
Application Performance) [1].

webrev: http://cr.openjdk.java.net/~mullan/webrevs/8072692/webrev.00/
bug: https://bugs.openjdk.java.net/browse/JDK-8072692

This fix adds several optimizations to the package matching algorithm 
used by the SecurityManager.checkPackageAcccess method. These 
improvements result in a 5-7x increase in throughput of this method. A 
performance chart has been attached to the bug with more information.

A new test is included which uses a state machine to verify that the 
matching algorithm is working correctly.

Special thanks to Daniel Fuchs for contributing this fix and the test.

Thanks,
Sean

[1] http://openjdk.java.net/jeps/232