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

[Aaron Ballman via cfe-commits]

AaronBallman 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?

Oh, I had missed that, sorry! Then no, a release note isn't needed.

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