Revert "Multiversioning- Ensure all MV functions are emitted."

This reverts commit 65df29f9318ac13a633c0ce13b2b0bccf06e79ca.

AS suggested by @rsmith here: https://reviews.llvm.org/rL345839
I'm reverting this and solving the initial problem in a different way.

llvm-svn: 348595