RFR(M): Graal PTX enhancements

[Morris Meyer]

Folks,

Could I get a review of my recent PTX enhancements to Graal?   I've 
changed the tests to have a base class, extended the assembler, and have 
taken the test coverage of PTX from 2 to 23 tests.

Thanks in advance,

         --morris meyer

WEBREV - http://cr.openjdk.java.net/~morris/Graal-PTX-Enhancements.01