Optimise binaries with wasm-opt

[RReverser]

Description of Changes

Now that our ABI checks can handle binaries produced by wasm-opt, we can use it (if installed) to optimise produced Wasm binaries.

For now it's added as an optional step until we figure out a decent deployment strategy to automatically get it for the user. (There are some wrappers on crates.io, but they tend to lag behind modern versions and take a while to compile, whereas Binaryen provides official prebuilt binaries on Github.)

This gives an easy 8-10% performance boost in iteration benchmarks, much more for an empty table but that's less interesting.

API and ABI

• This is a breaking change to the module ABI
• This is a breaking change to the module API
• This is a breaking change to the ClientAPI
• This is a breaking change to the SDK API

If the API is breaking, please state below what will break

Expected complexity level and risk

*How complicated do you think these changes are? Grade on a scale from 1 to 5,

1

This complexity rating applies not only to the complexity apparent in the diff,
but also to its interactions with existing and future code.

If you answered more than a 2, explain what is complex about the PR,
and what other components it interacts with in potentially concerning ways.

[kulakowski]

I'm really curious what optimizations are affecting our modules most.

[RReverser]

I'm really curious what optimizations are affecting our modules most.

That would need to be much deeper investigation and likely out of scope of this PR.

[gefjon]

Looks good. I appreciate not depending on wasm-opt, but encouraging users to install it. Long-term I wonder if we can link against binaryen rather than invoking it as a subprocess, but this is good for now.

[RReverser]

Long-term I wonder if we can link against binaryen rather than invoking it as a subprocess, but this is good for now.

Yeah I'd like that too. As I mentioned in the PR, there are some Rust wrappers that I was hoping to use, but they all tend to be outdated, and add non-trivial build time. It would be nice to figure out some cross-platform solution that doesn't involve rebuilds, but for now I don't see it.