back to the compile unit from the aranges section is to the skeleton
unit and not the one in the dwo.
Do this by adding a method to grab a forwarded on local sym and local
section by querying the skeleton if one exists and using that. Add
a few tests to verify the relocations are back to the correct section.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198202 91177308-0d34-0410-b5e6-96231b3b80d8
782b70f4b3