Revert "Reapply "DebugInfo: Ensure that all debug location scope chains from instructions within a function, lead to the function itself.""

This reverts commit r214761.

Revert while Reid investigates & provides a reproduction for an
assertion failure for this on Windows.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214999 91177308-0d34-0410-b5e6-96231b3b80d8