[clang] [clang] Fix crash when declaring invalid lambda member (PR #74110)

[Nikolas Klauser via cfe-commits]

philnik777 wrote:

@AaronBallman Thanks for the review. Sorry for responding so late - I've missed your review.

The tests aren't actually unrelated to the path. This is the file where I discovered the crash, so I just used it to demonstrate that it's fixed. I'm not sure how to split things, since I can't add the run line without fixing the bug.

https://github.com/llvm/llvm-project/pull/74110