Remove runtime flags for Proxy and Reflect

test/mjsunit/es6/proxies-define-property.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: --harmony-proxies
-
 // Check basic call to trap.
 
 var g_target, g_name, g_desc;
 var handler = {
   defineProperty: function(target, name, desc) {
     g_target = target;
     g_name = name;
     g_desc = desc;
     return true;
   }
@@ skipping 58 matching lines @@
 // Step 16a: Trap returns true for non-compatible property descriptor.
 Object.defineProperty(target, "foo",
                       {value: 1, writable: false, configurable: false});
 assertThrows("Object.defineProperty(proxy, 'foo', {value: 2})", TypeError);
 
 // Step 16b: Trap returns true for overwriting a configurable property
 // with a non-configurable descriptor.
 target.bar = "baz";
 assertThrows("Object.defineProperty(proxy, 'bar', {configurable: false})",
              TypeError);