[clang] [LifetimeSafety] Refactor FactGenerator to use RecursiveASTVisitor (PR #153661)

[Utkarsh Saxena via cfe-commits]

usx95 wrote:

>WDYT about this alternative of using a RAV driver ?

>>Hmm, there is a change that this could be a bit simpler than the current solution. If you can give this a try to see where does that lead it would be awesome.

Switched to using RAV for driving the FactGenerator @Xazax-hun 

https://github.com/llvm/llvm-project/pull/153661