[WebAssembly] Remove incorrect result from wasm64 store_lane instructions

The wasm64 versions of the v128.storeX_lane instructions was incorrectly defined
as returning a v128 value, which resulted in spurious drop instructions being
emitted and causing validation to fail. This was not caught earlier because
wasm64 has been experimental and not well tested. Update the relevant test file
to test both wasm32 and wasm64.

Fixes #62443.

Differential Revision: https://reviews.llvm.org/D149780