Change how isa_parser.py generates C++ names for isa_desc operands.

Change how isa_parser.py generates C++ names for isa_desc operands.

arch/isa_parser.py:
    Get rid of "munged name" for operands in C++ code.
    That is, "Ra.uq" will now be known in the C++ as "Ra"
    rather than "Ra_uq".  It wasn't legal to use different
    type extensions for the same operand at the same time
    anyway, and now it will be easier to refer to explicit
    operands in template code if necessary.

--HG--
extra : convert_revision : 9ff41e0201aeefe761743084ecdb34f4b9c84fdb