chore(lsp): test cover for wasm multi-value return types (#34652)

Closes denoland/divybot#385
Fixes https://github.com/denoland/deno/issues/29178

---------

Co-authored-by: divybot <divybot@users.noreply.github.com>
Co-authored-by: Divy Srivastava <me@littledivy.com>