Update Binaryen

[dcodeIO]

This PR updates Binaryen to latest, most notably accounting for

• Creation and expansion of multi-value types
• Removal of function types (API now takes multi-value types)
• Required type parameter when creating local.tees (currently polyfilled to the old behavior)

in turn also removing our own Binaryen-like signature handling. Signature changes are responsible for the huge fixture diff.

[jtenner]

Multivalue returns are going to open up the world for writing very efficient parsers.

[willemneal]

And can make iterators better too! Currently iterator.next() returns an object like {done: false, value: 1}, which would mean allocating a new object each iteration. I got around this in #862 by using the iterator itself as the return value. However, now we can just return the value and the done boolean!

Also tuples!!!

[dcodeIO]

Don't get too excited, as we don't have multi-value types yet. This is merely initial preparation on the Binaryen side. Also added a little test that doesn't validate at this point, but can be used to check in the future.