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

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

Is there a way to deprioritize these jobs relative to others (like the issue comments/PR subscribers jobs) so that the quick running jobs can run in between?

Also, it seems like the total time it takes for this workflow for a change to a project like LLVM will be many hours? I don't think that's going to be feasible given our 60 runner limit. When I last did the math, we would be reasonably comfortable with a turn-around time of 1-hour, and could maybe push a couple hours, but six hours from my previous estimates would definitely run into throughput limitations. Those numbers are somewhat old, but if anything, usage has gone up from what I've seen.

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