[proxies] Fix HasProperty and getOwnPropertySymbols

test/mjsunit/harmony/proxies-ownkeys.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 --harmony-reflect
 
 var target = {
   "target_one": 1
 };
 target.__proto__ = {
@@ skipping 56 matching lines @@
 assertThrows("Reflect.ownKeys(proxy)", TypeError);
 
 // Step 17a: The trap result must include all non-configurable keys.
 Object.defineProperty(target, "nonconf", {value: 1, configurable: false});
 keys = ["foo"];
 assertThrows("Reflect.ownKeys(proxy)", TypeError);
 keys = ["nonconf"];
 assertEquals(keys, Reflect.ownKeys(proxy));
 
 // Step 19a: The trap result must all keys of a non-extensible target.
-Object.freeze(target);
+Object.preventExtensions(target);
 assertThrows("Reflect.ownKeys(proxy)", TypeError);
 keys = ["nonconf", "target_one"];
 assertEquals(keys, Reflect.ownKeys(proxy));
 
 // Step 20: The trap result must not add keys to a non-extensible target.
 keys = ["nonconf", "target_one", "fantasy"];
 assertThrows("Reflect.ownKeys(proxy)", TypeError);