[clang] clang: Remove hacky OpenMP handling for appending bound arch (PR #201555)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 approved this pull request.

I'm assuming this was to handle the `-Xopenmp-target` thing? Should be fine as long as the tests still pass.

https://github.com/llvm/llvm-project/pull/201555