Make parachain validation wasm executor functional (#1574)

* Make parachain validation wasm executor functional

- Increase the size of the validation result in the shared memory. The
validation result holds the new runtime when a runtime upgrade is
scheduled. So, we need to give it enough memory to send the data between
the validator and the wasm execution host.
- Add the `CallInWasmExt`. This is required when doing a runtime upgrade
to check that we upgrade to something meaningful.

* Update parachain/src/wasm_executor/mod.rs

* Update parachain/src/wasm_executor/mod.rs

Co-authored-by: Nikolay Volf <[email protected]>

Co-authored-by: Nikolay Volf <[email protected]>