Run the `IOAppSpec` on Native

[armanbilge]

Another one I punted from my original PR.

In principle this is quite straightforward: we can re-use the existing technique of actually running the spec on the JVM but pointing it at either a JVM / JS / Native executable.

Because you cannot select a main method at runtime like JVM, it will also need to copy the JS technique of having a special main that emulates this behavior to choose from the various IOApps.

Finally, the tests will need to be subset again for the stuff we have not implemented on Native (like anything needing signal handlers).