Debug Info: revert r222195, r222210 and r222239.

This is no longer needed after David's fix at r222377 + r222485.
rdar://18958417


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222563 91177308-0d34-0410-b5e6-96231b3b80d8