[llvm] [LIT] Workaround the 60 processed limit on Windows (PR #157759)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 commented:

Are you able to add unit tests for the logic that figures out the number of pools to create/workers per pool, and the logic that distributes the tests? It looks correct to me after spending some time thinking about it, but I would rather not rely on my thinking being correct.

This adds a bit of complexity, but I think it's very much worth it given high core count systems are becoming increasingly popular. Thanks for working on this.

https://github.com/llvm/llvm-project/pull/157759