[clang] [coverage] fix crash in code coverage and `if constexpr` with `ExprWithCleanups` (PR #80292)

[Hana Dusíková via cfe-commits]

hanickadot wrote:

> Changes LGTM, but please add a release note to `clang/docs/ReleaseNotes.rst` so users know about the fix.
> 
> Thank you for the fix!

Even if it's a fix for recent PR I did few days ago?

Also, how do I get this into release branch (the previous change is there)?

https://github.com/llvm/llvm-project/pull/80292