Implement Wasmtime's new API as designed by RFC 11. This is quite a large commit which has had lots of discussion externally, so for more information it's best to read the RFC thread and the PR thread.
This is the test-programs crate, which builds and runs whole programs
compiled to wasm32-wasi.
To actually run these tests, the test-programs feature must be enabled, e.g.:
cargo test --features test-programs/test_programs --package test-programs