Support wide-arithmetic proposal

[marxin]

The proposal sits in the stage 3 right now:
https://github.com/WebAssembly/wide-arithmetic

Would be nice to have it covered in the binaryen.

[MaxGraey]

Looks like a lot of runtimes already experimentally support this

[stevenfontanella]

TODOs for this:

• Feature flag
• Interpreter + optimizer support for the new instructions
  • Once we have this, we should also do end-to-end performance tests with V8, in particular to see whether multi-value returns optimize well.
• Fuzzing support
• C + JS API