Support wasm32 for recorded tests

We should consider supporting recorded tests for `wasm32-unknown-unknown` and friends. When resolving #1877 I made it possible to compile it, but we can't spawn processes for the wasm32 architecture so the core functionality doesn't work. Prior to that, the `#[recorded::test]` attribute already elides tests for wasm32.

We should be able to support it, however, if we require people to start it manually i.e., not bootstrap it automatically, and find some way to pass the URL.

Start by examining the `#[recorded::test]` attribute and the wasm32 compilation work from #1877. Determine how manually started services and their URL could be supplied without process spawning; done means recorded tests run on wasm32-unknown-unknown and related targets. The issue does not name files or tests.

Written by the indexing model from the issue text.