Use correct trap for lookup in prototype proxy.

test/mjsunit/harmony/proxies.js

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 591 matching lines @@
   assertEquals("p_nonconf", key)
 
   assertThrows(function(){ o.p_throw = 51 }, "myexn")
   assertEquals("p_throw", key)
 
   assertThrows(function(){ o.p_setterthrow = 52 }, "myexn")
   assertEquals("p_setterthrow", key)
 }
 
 TestSetForDerived({
-  getOwnPropertyDescriptor: function(k) {
+  getPropertyDescriptor: function(k) {
     key = k;
     switch (k) {
       case "p_writable": return {writable: true, configurable: true}
       case "p_nonwritable": return {writable: false, configurable: true}
       case "p_setter":return {set: function(x) { val = x }, configurable: true}
       case "p_nosetter": return {get: function() { return 1 }, configurable: true}
       case "p_nonconf":return {}
       case "p_throw": throw "myexn"
       case "p_setterthrow": return {set: function(x) { throw "myexn" }}
       default: return undefined
@@ skipping 1723 matching lines @@
 
 TestAccessorCall(
   Proxy.createFunction({}, function() { receiver = this; return 42 }),
   Proxy.createFunction({}, function(x) { receiver = this; value = x })
 )
 
 TestAccessorCall(
   CreateFrozen({}, function() { receiver = this; return 42 }),
   CreateFrozen({}, function(x) { receiver = this; value = x })
 )