request for review (XS)

[Keith McGuigan]

http://webrev.invokedynamic.info/kamg/6705523/

This fix has the classfiler parser accept classfiles with version 51 
only when the VM is run in the context of JDK7 (or greater).  For JDK6, 
version 50 is the max accepted classfile version.

The change in sharedRuntime_sparc.cpp is an unrelated change to 
eliminate a compile warning.

Thanks for any review.

--
- Keith