wat2wasm demo seems a little outdated

[Sainan]

https://webassembly.github.io/wabt/demo/wat2wasm/ errors on the following code even with exceptions checked on:

(module
  (tag $e0)
  (func (export "simple-throw-catch") (param i32) (result i32)
    (block $h
      (try_table (result i32) (catch $e0 $h)
        (if (i32.eqz (local.get 0)) (then (throw $e0)) (else))
        (i32.const 42)
      )
      (return)
    )
    (i32.const 23)
  )
)

but the downloaded wat2wasm with --enable-exceptions handles this fine.

[spotandjake]

The problem here is that make demo isn't called on release, my pr #2568 should update libwabt.js to a slightly newer version but it would probably make sense to call make demo on release.

[kevmoo]

See #2720

I agree it should be done as part of build or similar.