[clang] [LifetimeSafety] Revamp how accesses and uses are handled (PR #225799)

[Gábor Horváth via cfe-commits]

Xazax-hun wrote:

> Double checking that this is still orthogonal the large #false positive in invalidations:

Yes, we need to update the loan representations to handle this. But this will help us avoid some common false positives once we model thee patterns more precisely in the loans. 

https://github.com/llvm/llvm-project/pull/225799