Remove destructuring and default arguments runtime flags

test/mjsunit/es6/debug-step-destructuring-bind.js

 // Copyright 2015 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: --expose-debug-as debug --harmony-destructuring-bind
+// Flags: --expose-debug-as debug
 
 var exception = null;
 var Debug = debug.Debug;
 var break_count = 0;
 
 function listener(event, exec_state, event_data, data) {
   if (event != Debug.DebugEvent.Break) return;
   try {
     var source = exec_state.frame(0).sourceLineText();
     print(source, break_count);
@@ skipping 85 matching lines @@
   var {
     x: a,                                         // B46
     y: b = 9                                      // B47
   } = { x: 4 };
   assertEquals([4, 9], [a, b]);                   // B48
 }                                                 // B49
 
 test();
 Debug.setListener(null);                          // B50
 assertNull(exception);