Revert "Re-land "[MergeICmps] Disable mergeicmps if the target does not want to handle memcmp expansion."""

broken test on windows

This reverts commit c91479518344fd1fc071c5bd5848f6eb83e53dca.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314985 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed