Remove runtime flags for Proxy and Reflect

test/mjsunit/es6/proxies-get-prototype-of.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 target = { target: 1 };
 target.__proto__ = {};
 var handler = { handler: 1 };
 var proxy = new Proxy(target, handler);
 
 assertSame(Object.getPrototypeOf(proxy), target.__proto__ );
 
 target.__proto__ = [];
 assertSame(Object.getPrototypeOf(proxy), target.__proto__);
 
@@ skipping 67 matching lines @@
   assertFalse(Object.prototype.isPrototypeOf.call({}, object));
   assertTrue(Object.prototype.isPrototypeOf.call(Object.prototype, object));
 
   handler.getPrototypeOf = function () { return object };
   assertTrue(Object.prototype.isPrototypeOf.call(object, object));
 
   handler.getPrototypeOf = function () { throw "foo" };
   assertThrows(()=> Object.prototype.isPrototypeOf.call(object, object));
   assertThrows(()=> Object.prototype.isPrototypeOf(object));
 })();