[clang] [LifetimeSafety] Overhaul CFG and analysis to also work with trivially destructed temporary objects (PR #177985)

[Gábor Horváth via cfe-commits]

Xazax-hun wrote:

> My only worry is that the analysis-related changes are ~30 lines of changes I think. So it might be too small as a meaningful PR maybe? 

There is no such thing as too small PR. The smaller the better, it makes several things easier:
* Reviews are quicker
* Bisecting a bug is more precise, easier to find the root cause
* It is possible to revert the second part without the first one

https://github.com/llvm/llvm-project/pull/177985