[mjsunit] remove unnecessary AsyncFunction

test/mjsunit/harmony/async-function-debug-scopes.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --harmony-async-await --expose-debug-as debug
 
 var Debug = debug.Debug;
 
-var AsyncFunction = (async function() {}).constructor;
-
 async function thrower() { throw 'Exception'; }
 
 async function test(name, func, args, handler, continuation) {
   var handler_called = false;
   var exception = null;
 
   function listener(event, exec_state, event_data, data) {
     try {
       if (event == Debug.DebugEvent.Break) {
         handler_called = true;
@@ skipping 586 matching lines @@
     assertTrue(response.body.object.ref < 0);
   } else {
     assertTrue(response.body.object.ref >= 0);
   }
   var found = false;
   for (var i = 0; i < response.refs.length && !found; i++) {
     found = response.refs[i].handle == response.body.object.ref;
   }
   assertTrue(found, "Scope object " + response.body.object.ref + " not found");
 }