[clang] [ObjC] Check entire chain of superclasses to see if class layout can be statically known (PR #81335)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> @rjmccall Are these tests adequate?

While we appreciate the enthusiasm, please only ping reviewers after about a week of not hearing from them on a review (https://llvm.org/docs/CodeReview.html#code-reviews-speed-and-reciprocity), thanks!

https://github.com/llvm/llvm-project/pull/81335