[X86] Fix the SchedRW for memory forms of CMP and TEST.

[X86] Fix the SchedRW for memory forms of CMP and TEST.

They were incorrectly marked as RMW operations. Some of the CMP instrucions worked, but the ones that use a similar encoding as RMW form of ADD ended up marked as RMW.

TEST used the same tablegen class as some of the CMPs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327947 91177308-0d34-0410-b5e6-96231b3b80d8