Since there's no way to ensure the type unit in the .dwo and the type
unit skeleton in the .o are correlated, this cannot work.
This implementation is a bit inefficient for a few reasons, called out
in comments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207323 91177308-0d34-0410-b5e6-96231b3b80d8