[clang] [LifetimeSafety] Model scope-exit destructor and cleanup callback as a use (PR #204650)

[Gábor Horváth via cfe-commits]

Xazax-hun wrote:

Makes sense, done. For #3, I agree with your concerns but a potential refactor should probably be a different PR. 

https://github.com/llvm/llvm-project/pull/204650