[clang] [llvm] [DirectX] Add `--dx-embed-debug` and `--dx-pdb-path` flags (PR #204166)

[Jessica Clarke via cfe-commits]

jrtc27 wrote:

(Fixing forward is also ok if there's an obvious quick fix for it, but please do not use that as a source of delay)

https://github.com/llvm/llvm-project/pull/204166