[llvm] Workflows: Use new depot runners for x86 Linux release builds (PR #117111)

[Tom Stellard via llvm-commits]

tstellar wrote:

> > I agree, but we can't drop the multi-stage builds until we get more powerful mac/Windows runners to use. I thought about splitting the workflow, but the main reason I didn't is that I thought there would be too much duplication between the two workflows. I could try to factor out the common stuff and put it in a composite action, and I can do that if you think it will be better.
> 
> Does Depot support MacOS/Windows jobs? I know AWS at least has instances for both.

Depot supports AArch64 macOS, I'm not sure they support X86 though.  Windows is not supported yet.

https://github.com/llvm/llvm-project/pull/117111