These fixes now allow all of the 20 mips tests to work properly!

These fixes now allow all of the 20 mips tests to work properly!
Floating Point Mips Tests still need to be added, tested, and debugged.

arch/mips/isa/decoder.isa:
    Fix mult and multu instructions. This semantic error causes the problem: <int64> = <int32> * <int32>. Although I was placing
    the output into a 64-bit integer the multiply was just doing a 32-bit multiply so the solution is to just use
    the 'sd' & 'ud' operands so that the ISA parser will use the int64_t and uint64_t types in calculation.
arch/mips/isa/formats/int.isa:
    Trace output fix. Don't print first comma unless there is a destination register for sure!

--HG--
extra : convert_revision : 2c503dca70b104fed0b58454975f745dd3cc2eee