[llvm] [Uniformity] Implement per-output machine uniformity analysis (PR #179275)

[Pankaj Dwivedi via llvm-commits]

PankajDwivedi-25 wrote:

> I don't know what's the value of an NFC patch. Patches should not be split just for the sake of making small patches.

For the simplicity of code review, it will unnecessarily add more things, which may shadow the actual patch.

https://github.com/llvm/llvm-project/pull/179275