native WASI conformance test suite #885

Working on wasip3 implementation code I found the component model conformance tests very helpful, making me wish there was an equivalent for the high level APIs. I know of proposal #9 to introduce a WASI test suite, and wasi-testsuite and the different tests in existing runtimes exist as well. But since WASI can already do much, I think it would be valuable to have a WASI testsuite you could run on WASI implementation without any extra requirements. What WASI extensions would make that possible? Maybe a form of exec is enough?