[llvm] [Object][Wasm] Move wasm Object tests into their own directory (NFC) (PR #81072)

[David Blaikie via llvm-commits]

dwblaikie wrote:

> I think maybe go for a full rename for ELF and COFF too? See what the other maintainers think about it?
I assume there are sufficiently interesting differences to test between AArch64 and ARM, etc. but there's no architecture variants for wasm or webassembly - Yeah, there might be different ways of naming things between the format and the architecture, but I think the distinction isn't especially important to make - but I think it's fine/suitable for it to have a separate directory (I don't too much mind what name - but I agree consistency is nice to have, and if we've mostly used `WebAssembly` eswhere, let's use it here).

https://github.com/llvm/llvm-project/pull/81072