[llvm-mca][x86] Add CMPXCHG instruction resource tests

I've put CMPXCHG8B/CMPXCHG16B in the same file, even though technically they are under separate CPUID bits all targets seem to support both (or neither).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338595 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed