Revert "r219834 - Teach ScalarEvolution to sharpen range information"

This change breaks the asan buildbots:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/13468



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219878 91177308-0d34-0410-b5e6-96231b3b80d8