[SystemZ] Add support for TMHH, TMHL, TMLH and TMLL

For now just handles simple comparisons of an ANDed value with zero.
The CC value provides enough information to do any comparison for a
2-bit mask, and some nonzero comparisons with more populated masks,
but that's all future work.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189469 91177308-0d34-0410-b5e6-96231b3b80d8