Add WASI printf test

test/wasi/README.md

@@ -0,0 +1,15 @@
+## Compile
+
+```sh
+wasicc -Oz wasi_printf.c -o wasi_printf.wasm
+
+# Disassemble:
+wasm2wat wasi_printf.wasm -o wasi_printf.wat
+```
+
+## Run
+
+```sh
+../../build/wasm3 wasi_printf.wasm _start
+```
+

test/wasi/wasi_printf.c

@@ -0,0 +1,8 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+int main(int args, char* argv[]) {
+    //puts("Hello world!");
+    printf("Hell%x w%d%s!\n", 0, 0, "rld");
+    return 0;
+}