Revert "DebugInfo: Generalize debug info location handling"

Fails an ASan bootstrap - I'll try to reproduce locally & sort that out
before recommitting.

This reverts commit r224385.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@224441 91177308-0d34-0410-b5e6-96231b3b80d8