Remove use of reverse iterators in repairIntervalsInRange(). While they were
arguably better than forward iterators for this use case, they are confusing and
there are some implementation problems with reverse iterators and MI bundles.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175393 91177308-0d34-0410-b5e6-96231b3b80d8