[runtime] Object.create(null) creates a slow object

test/mjsunit/harmony/private.js

 // Copyright 2013 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 277 matching lines @@
 function TestKeyDelete(obj) {
   for (var i in symbols) {
     delete obj[symbols[i]]
   }
   for (var i in symbols) {
     assertEquals(undefined, Object.getOwnPropertyDescriptor(obj, symbols[i]))
   }
 }
 
 
-var objs = [{}, [], Object.create(null), Object(1), new Map, function(){}]
+var objs = [{}, [], Object.create({}), Object(1), new Map, function(){}]
 
 for (var i in objs) {
   var obj = objs[i]
   TestKeySet(obj)
   TestKeyDefine(obj)
   TestKeyGet(obj)
   TestKeyHas(obj)
   TestKeyEnum(obj)
   TestKeyNames(obj)
   TestKeyDescriptor(obj)
@@ skipping 86 matching lines @@
 
   // Test non-monomorphic.
   for (var i = 0; i < 1000; i++) {
     var oNew = Object.create(p);
     oNew["s" + i] = i;
     oNew[s1] = "bow-wow";
     checkNonOwn(oNew);
   }
 }
 TestICs();