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

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

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

Nope, it's ready to land; sorry for not asking earlier, do you need me to commit this on your behalf?

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