Move the re-stemming function up top and use it where it's currently inlined.

Move the re-stemming function up top and use it where it's currently inlined.
Break the arc-profile code out to a function like the notes emission code is,
and reorder the functions in the file.

The only functionality change is that we no longer modify the Module when the
Module has no debug info to use.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129631 91177308-0d34-0410-b5e6-96231b3b80d8