Investigate caching wasm file

[dsherret]

IIRC, I think right now it downloads on every run? Not good. (maybe this just requires updating wasmbuild)

[andrewbrey]

I learned this on an airplane last weekend! Indeed, as of now, some wasm file is downloaded every run and so even if you cache the other modules in the graph, network access is still required to run dax code - documenting or mitigating this would be very helpful 👍

[dsherret]

I also discovered this while on an airplane 😅

I'm going to mitigate it for now (shouldn't be up to the user to have to worry about this). Soon Deno will support wasm files as being part of the module graph so the whole situation will be better.