Refactor WASM module instantiation (#10480)

* Refactor WASM module instantiation; enable WASM instance pooling

* Disable the `uffd` feature on `wasmtime`

* Restore the original behavior regarding the initial WASM memory size

* Adjust error message

* Remove unnecessary import in the benchmarks

* Preinstantiate the WASM runtime for a slight speedup

* Delete the asserts in `convert_memory_import_into_export`

* `return` -> `break`

* Revert WASM instance pooling for now

* Have `convert_memory_import_into_export` return an error instead of panic

* Update the warning when an import is missing

* Rustfmt and clippy fix

* Fix executor benchmarks' compilation without `wasmtime` being enabled

* rustfmt again

* Align to review comments

* Extend tests so that both imported and exported memories are tested

* Increase the number of heap pages for exported memories too

* Fix `decommit_works` test