[clang] [Clang] skip alignment checks on incomplete types to avoid an assertion failure while parsing lambda used as default argument (PR #94542)

[Oleksandr T. via cfe-commits]

a-tarasyuk wrote:

@AaronBallman Thank you for your feedback. Do you think this needs to be reviewed by someone else? I can't add reviewers myself :)

https://github.com/llvm/llvm-project/pull/94542