[llvm] [CodeGen] Expose the extensibility of PassConfig to plugins (PR #139059)

[Stefan Gränitz via llvm-commits]

weliveindetail wrote:

I am planning to land this tomorrow morning CEST, because I am out on Friday. @Tcc100 Should I land the patch on behalf of `T<T>`? Otherwise, please let me know the proper attribution -- here or via email (you find it in my LLVM patches 😉)

https://github.com/llvm/llvm-project/pull/139059