Revert "DebugInfo: Generalize debug info location handling"

Asserting when building compiler-rt when using a GCC host compiler.
Reverting while I investigate.

This reverts commit r224941.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@224970 91177308-0d34-0410-b5e6-96231b3b80d8