Malformed br_on_null and br_on_non_null in tests

[osa1]

• https://github.com/WebAssembly/function-references/blob/159e41b60ccab78bb817ac6903480eabed538cbd/test/core/br_on_non_null.wast#L59
• https://github.com/WebAssembly/function-references/blob/159e41b60ccab78bb817ac6903480eabed538cbd/test/core/br_on_null.wast#L53

These uses of br_on_null and br_on_non_null take 3 arguments, instead of 2, and the reference arguments (2nd arguments) are i32s.

[osa1]

Just realized that those extra arguments are as arguments to the target branch. Sorry for the noise.