Reland "[ARM] push LR before __gnu_mcount_nc"

This relands r369147 with fixes to unit tests.

https://reviews.llvm.org/D65019

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@369173 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed