[Debugify] Set a DI version module flag for llc compatibility

Setting the "Debug Info Version" module flag makes it possible to pipe
synthetic debug info into llc, which is useful for testing backends.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333237 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed