Test/Example for WebAssembly

[Niederb]

It would be nice to have an example that works with WebAssembly. We should also have some tests that run a WebAssembly executable.
Some of the existing examples might actually work but it would still be nice to document this.

• Find/Write an example that works with wasm
  • Run this example with a wasm runtime
• Documentation
  • What does work with WebAssembly
  • Differences between wasm-unknown-unknown and wasm-wasip1
  • Differences no_std and wasm

[Niederb]

Using the kitchensink_runtime seems very problematic. As soon as it is included the wasm module cannot be instantiated anymore 👎

Error: failed to run main module `target/wasm32-unknown-unknown/release/examples/wasm_example.wasm`

Caused by:
    0: failed to instantiate "target/wasm32-unknown-unknown/release/examples/wasm_example.wasm"
    1: unknown import: `env::ext_trie_blake2_256_ordered_root_version_2` has not been defined

[masapr]

@Niederb What's your suggestion on how we should continue with this? Should we try to fix this in the kitchensink_runtime (with the goal to do a PR there?) or create an example with a different runtime? Or just pause this issue and try again in the future?

[Niederb]

I already worked quite a bit on the test infrastructure. At least a very minimal example should be possible and I think having something running with WebAssembly would already be useful.