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

[Ella Ma via cfe-commits]

Snape3058 wrote:

> The changes should come with a release note in `clang/docs/ReleaseNotes.rst` so users know about them.

Do I need to add this directly to the release note in this commit? Or will we do that later when releasing?

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