[clang] Fix erroneous warning. (PR #79821)

[Zahira Ammarguellat via cfe-commits]

zahiraam wrote:

> Thank you for the fix! Can you add some more description to the patch summary as to what's erroneous (the summary ends up becoming the commit message, so a terse summary can be harmful for later code archeology).
> 
> Do we need a release note for this? Are you planning to cherry-pick this to the 18.x branch?

I don't think we need a Release note for it since this was a faulty behavior to start with. It's not related to any of the options.

Would be nice to cherry-pick. Not sure how to do that though.

https://github.com/llvm/llvm-project/pull/79821