[llvm] [ConstraintElim] Add facts implied by llvm.abs (PR #73189)

[Florian Hahn via llvm-commits]

fhahn wrote:

> @fhahn - yup, I'm planning to send a follow-up PR ~this week (if it's not urgent)

Sounds great, just wanted to check, it's not urgent at all.

https://github.com/llvm/llvm-project/pull/73189