[llvm] [CI] Rework github workflow processing (PR #130317)

[Nathan Gauër via llvm-commits]

Keenuts wrote:

> I didn't even consider the case where we hit a completed workflow that shadowed other completed workflows due to them being ordered by start time. That's a good catch.


Yes, I realized that very late.. So we probably had better metrics than reality because of this.

> It looks like we may need to increase the max depth though based on what I saw on the dashboard today.

Yes, seems like yesterday was a pretty busy day, but we might want to double it soon.


https://github.com/llvm/llvm-project/pull/130317