Revert "[ScalarEvolution] Handling for ICmp occuring in the evolution chain."

This reverts commit r316054.  There was some confusion over the review process:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20171016/495884.html

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316129 91177308-0d34-0410-b5e6-96231b3b80d8