Handled all compressed instructions except for
Q (128 bit) instructions and nop (addi x0, x0, 0i,
which requires a change in the instruction definition).
- checkEarlyTargetMatchPredicate was defined
to enforce tied operands otherwise compressed version
is picked even when operands are not tied.
- Hint variable set to false to allow repeated operands
in AsmString 'add $rs1, $rs1, $rs2".
- AsmMatcherEmitter.cpp 'Operator <' was updated to
check for required features before ordering unrelated
UserClasses by UserClass name. This affects instructions
with immediates since immediate classes are usually unrelated.