Remove the COFF files with Z7 debug info from the repo

Rationale: going to land D2425 shortly.
I'll re-land these COFF files along with D2425 to simplify the SVN history

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197673 91177308-0d34-0410-b5e6-96231b3b80d8