for review (L): 6858164: invokedynamic code needs some cleanup (post-6655638)

[John Rose]

http://cr.openjdk.java.net/~jrose/6858164/vm-webrev.01/

Summary:  These are fixes for method handles proper.
- correctly raises exceptions
- supports safe bitwise "raw" conversions (e.g., int -> void)
- fixes bugs (various, small) revealed by VerifyMethodHandles
- dead code is removed
- debugging support is improved

Still to follow:
- more bug fixes to the invokedynamic instruction
- runtime simplification for invokedynamic
- compiler support for invokedynamic
- inlining of method handles
- API adjustments that affect the JVM (mainly, removing private  
supertypes)