[clang] [clang][bytecode] fix assertion failure on invalid init list (GH175432) (PR #180261)

[Timm Baeder via cfe-commits]

tbaederr wrote:

I can't give you a definitive answer to that, I'd have to try myself and see what tests break if I do that. I think it's weird that the declaration doesn't get marked as invalid but maybe that ends up being important, I don't know yet.

https://github.com/llvm/llvm-project/pull/180261