make runtime compatible with wasm

runtime/internal/lib/os/os_wasm.go

@@ -0,0 +1,10 @@
+package os
+
+// setStickyBit adds ModeSticky to the permission bits of path, non atomic.
+func setStickyBit(name string) error {
+	return nil
+}
+
+func Chmod(name string, mode FileMode) error {
+	return nil
+}