6797305: Add LoadUB and LoadUI opcode class
Summary: Add a LoadUB (unsigned byte) and LoadUI (unsigned int) opcode class so we have these load optimizations in the first place and do not need to handle them in the matcher.
Reviewed-by: never, kvn
6812831: factor duplicated assembly code for megamorphic invokeinterface (for 6655638)
Summary: Code in vtableStubs and templateTable moved into MacroAssembler.
Reviewed-by: kvn
6812678: macro assembler needs delayed binding of a few constants (for 6655638)
Summary: minor assembler enhancements preparing for method handles
Reviewed-by: kvn