[llvm] [SCEV] Introduce SCEVUse, use it instead of const SCEV * (NFCI) (WIP). (PR #91961)

[Florian Hahn via llvm-commits]

fhahn wrote:

Ping. Any thoughts about the overall direction? There are a number of places where context-specific SCEV flags could be helpful, with my main interest being on LAA at the moment.

https://github.com/llvm/llvm-project/pull/91961