[X86] Regenerate memcmp tests and add X64-AVX512 common prefix
[X86] Regenerate memcmp tests and add X64-AVX512 common prefix

Should help make the changes in D69157 clearer

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@375215 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm