[llvm] [workflows] Port buildkite Windows config to GitHub actions (PR #82093)

[Vlad Serebrennikov via llvm-commits]

Endilll wrote:

Going beyond 5 hours by design sounds risky to me, as I don't expect GitHub runners to have a very consistent performance. On top of that, we also should accommodate growth of the projects. As https://llvm-compile-time-tracker.com/graphs.php shows, over time it takes more effort to build Clang.

What the testing environment was? Were you using Clang with PGO trained on building LLVM or Clang?

https://github.com/llvm/llvm-project/pull/82093