[llvm] CodeGen: replace assertions with explicit errors for landinpad lowering (PR #71287)

[via llvm-commits]

AlexDenisov wrote:

Hi @arsenm, I created another PR this time adding the logic to the verifier instead of erroring during codegen: https://github.com/llvm/llvm-project/pull/87198

The new PR is still in draft mode while I'm trying to figure out why CI is red, but I'd appreciate if you can confirm that this is a better approach/right direction, I'd be happy to iterate on it 🙇

https://github.com/llvm/llvm-project/pull/71287