[proxies] Fix Object.prototype.hasOwnProperty

test/mjsunit/harmony/proxies-has-own-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
 
 var handler = {};
 var target = {a:1};
 var proxy = new Proxy(target, handler);
 
 assertTrue(target.hasOwnProperty('a'));
 assertTrue(proxy.hasOwnProperty('a'));
 assertFalse(target.hasOwnProperty('b'));
 assertFalse(proxy.hasOwnProperty('b'));
 
 
-handler.has = function() {
-  return false;
-}
+handler.has = function() { assertUnreachable() }
+handler.getOwnPropertyDescriptor = function () {}
+
 assertTrue(target.hasOwnProperty('a'));
 assertFalse(proxy.hasOwnProperty('a'));
 assertFalse(target.hasOwnProperty('b'));
 assertFalse(proxy.hasOwnProperty('b'));
 
-handler.has = function() {
-  return true;
-}
+
+handler.getOwnPropertyDescriptor = function() { return {configurable: true} }
+
 assertTrue(target.hasOwnProperty('a'));
 assertTrue(proxy.hasOwnProperty('a'));
 assertFalse(target.hasOwnProperty('b'));
 assertTrue(proxy.hasOwnProperty('b'));
 
-handler.has = function() {
-  throw Error();
-}
+
+handler.getOwnPropertyDescriptor = function() { throw Error(); }
+
 assertTrue(target.hasOwnProperty('a'));
 assertThrows(function(){ proxy.hasOwnProperty('a') }, Error);
 assertFalse(target.hasOwnProperty('b'));
 assertThrows(function(){ proxy.hasOwnProperty('b') }, Error);