[clang] [analyzer] Ignoring `T v=v; ` idiom for uninitialized variable checker and dead store checker (PR #187530)

[Balázs Benics via cfe-commits]

https://github.com/steakhal approved this pull request.

I didn't follow the discussion but I'm okay with what's presented here.
The static analyzer mostly hunts for UB, and in this case honouring this self init pattern does not limit that capability.

Please wait for consensus on this thread before merging.

https://github.com/llvm/llvm-project/pull/187530