Revert "Convert `obj` ToObject in Object.keys()"

src/v8natives.js

 // Copyright 2012 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.
 
 // This file relies on the fact that the following declarations have been made
 // in runtime.js:
 // var $Object = global.Object;
 // var $Boolean = global.Boolean;
 // var $Number = global.Number;
 // var $Function = global.Function;
@@ skipping 307 matching lines @@
 function ObjectLookupSetter(name) {
   var receiver = this;
   if (receiver == null && !IS_UNDETECTABLE(receiver)) {
     receiver = %GlobalProxy(global);
   }
   return %LookupAccessor(ToObject(receiver), ToName(name), SETTER);
 }
 
 
 function ObjectKeys(obj) {
-  obj = ToObject(obj);
+  if (!IS_SPEC_OBJECT(obj)) {
+    throw MakeTypeError("called_on_non_object", ["Object.keys"]);
+  }
   if (%IsJSProxy(obj)) {
     var handler = %GetHandler(obj);
     var names = CallTrap0(handler, "keys", DerivedKeysTrap);
     return ToNameArray(names, "keys", false);
   }
   return %OwnKeys(obj);
 }
 
 
 // ES5 8.10.1.
@@ skipping 1562 matching lines @@
   }
   if (!IS_SPEC_FUNCTION(method)) {
     throw MakeTypeError('not_iterable', [obj]);
   }
   var iterator = %_CallFunction(obj, method);
   if (!IS_SPEC_OBJECT(iterator)) {
     throw MakeTypeError('not_an_iterator', [iterator]);
   }
   return iterator;
 }