As a step towards getting rid of internal pass manager hack entirely, remove the need for loop simplify to run in the inner pass manager. The new code does produce slightly different loop structures, so this isn't technically NFC.
Differential Revision: http://reviews.llvm.org/D9585
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237172 91177308-0d34-0410-b5e6-96231b3b80d8