[lld] [lld][WebAssembly] Work around limited architecture detection for wasm64 shared libraries (PR #98961)

[Heejin Ahn via llvm-commits]

aheejin wrote:

So this makes wasm-ld not error out on shared objs? Then what if the arch (determined by the heuristic) is incorrect?

https://github.com/llvm/llvm-project/pull/98961