Disabling the transformation introduced in r315888

The commit at https://reviews.llvm.org/rL315888 is causing some failures
with internal testing. Disabling this code until we can resolve the issues.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316199 91177308-0d34-0410-b5e6-96231b3b80d8