Initial reorg.

This is largely the same as #305, but updated for the current tree.

crates/wasi-common/tests/wasm_tests/main.rs

@@ -0,0 +1,16 @@
+#![cfg(feature = "wasm_tests")]
+
+mod runtime;
+mod utils;
+
+use std::sync::Once;
+
+static LOG_INIT: Once = Once::new();
+
+fn setup_log() {
+    LOG_INIT.call_once(|| {
+        pretty_env_logger::init();
+    })
+}
+
+include!(concat!(env!("OUT_DIR"), "/wasi_misc_tests.rs"));