[lld] [lld][WebAssembly] Fix use of undefined funcs under --warn-unresolved-symbols (PR #78643)

[Sam Clegg via llvm-commits]

sbc100 wrote:

That failure looks like its is in the elf linker, so I think it cannot be related to this change, unless I'm missing something.

https://github.com/llvm/llvm-project/pull/78643