[llvm] [CodeGen] Diagnose unsupported landingpad result types instead of asserting (PR #223205)

[Reid Kleckner via llvm-commits]

https://github.com/rnk approved this pull request.

Looks good, but in the future, please author pr descriptions without agent assistance. It reads like agent-speak ("shape", "takes down whole compiler").

We could also drop the release note. I consider this a quality of implementation improvement.

https://github.com/llvm/llvm-project/pull/223205