977: fix(runtime-core) Remove unnecessary implementation of `WasmTypeList` r=Hywan a=Hywan
The unit tests `test_func_arity_*` covers all possibilities, from 0 to
12. Removing this specific implementation of `WasmTypeList` for `(A,)`
doesn't break the test cases.
Also, the `impl_traits!` macro already implement `WasmTypeList` for
`(A,)` with `impl_traits!([transparent] S1, A)`. It's not clear why
`rustc` doesn't detect that though.
Co-authored-by: Ivan Enderlin <ivan.enderlin@hoa-project.net>