[clang] [Clang] Forward `-Xarch_<arch> -Wl,foo` for GPU toolchains (PR #126248)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> And just now another failure: https://lab.llvm.org/buildbot/#/builders/190/builds/14342

Honestly, I don't know. I'd say that it's because we don't support offloading on Darwin, but the triple is supposed to be x64. I could probably just set the test to unsupported for darwin since GPU offloading isn't supported there.

https://github.com/llvm/llvm-project/pull/126248