Remove runtime flags for Proxy and Reflect

test/mjsunit/harmony/proxies-property-is-enumerable.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
-
-var handler = {};
-var target = { a: 1 };
-var proxy = new Proxy(target, handler);
-
-assertTrue(target.propertyIsEnumerable('a'));
-assertTrue(proxy.propertyIsEnumerable('a'));
-assertFalse(target.propertyIsEnumerable('b'));
-assertFalse(proxy.propertyIsEnumerable('b'));
-
-handler.getOwnPropertyDescriptor = function(target, prop) {
-  return { configurable: true, enumerable: true, value: 10 };
-}
-assertTrue(target.propertyIsEnumerable('a'));
-assertTrue(proxy.propertyIsEnumerable('a'));
-assertFalse(target.propertyIsEnumerable('b'));
-assertTrue(proxy.propertyIsEnumerable('b'));
-
-handler.getOwnPropertyDescriptor = function(target, prop) {
-  return { configurable: true, enumerable: false, value: 10 };
-}
-assertTrue(target.propertyIsEnumerable('a'));
-assertFalse(proxy.propertyIsEnumerable('a'));
-assertFalse(target.propertyIsEnumerable('b'));
-assertFalse(proxy.propertyIsEnumerable('b'));