[lld] [lld][WebAssembly] Match the ELF linker in transitioning away from archive indexes. (PR #78658)

[Fangrui Song via llvm-commits]

MaskRay wrote:

Thanks for removing `--fatal-warnings`. I agree that switching to an object file for wasm as well is the right move.

The ELF port warning about a non-object file is related to: traditional linkers ignore these files, and these files if textual, cannot be differentiated with linker scripts. A warning informs the user that the text file is not interpreted as a linker script. Non-object-files as archive members are weird anyway.

https://github.com/llvm/llvm-project/pull/78658