fix tests

tests/send.cm

@@ -0,0 +1,10 @@
+return {
+    test_send: function() {
+        $_.start(e => {
+          send(e.actor, { message: "Hello! Good to go?" }, msg => {
+            log.console(`Original sender got message back: ${json.encode(msg)}. Stopping!`)
+            // $_.stop() // Removed
+          })
+        }, "tests/reply_actor")
+    }
+}