[llvm-branch-commits] [llvm] [Github] Remove install-ninja/setup-windows (PR #168985)

[Deric C. via llvm-branch-commits]

Icohedron wrote:

This change broke all the bots in the [llvm/offload-test-suite](https://github.com/llvm/offload-test-suite) repo because all the workflows there use the setup-windows action.

https://github.com/llvm/llvm-project/pull/168985