Rename IS_SPEC_OBJECT macro to IS_RECEIVER.

src/js/harmony-reflect.js

 // Copyright 2013-2015 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.
 
 (function(global, utils) {
 
 'use strict';
 
 %CheckIsBootstrapping();
 
 // -------------------------------------------------------------------
 // Imports
 
 var GlobalReflect = global.Reflect;
 var MakeTypeError;
 var ReflectApply = utils.ImportNow("reflect_apply");
 var ReflectConstruct = utils.ImportNow("reflect_construct");
 
 utils.Import(function(from) {
   MakeTypeError = from.MakeTypeError;
 });
 
 // -------------------------------------------------------------------
 
 function ReflectEnumerate(obj) {
-  if (!IS_SPEC_OBJECT(obj))
+  if (!IS_RECEIVER(obj))
     throw MakeTypeError(kCalledOnNonObject, "Reflect.enumerate")
   return (function* () { for (var x in obj) yield x })();
 }
 
 utils.InstallFunctions(GlobalReflect, DONT_ENUM, [
   "apply", ReflectApply,
   "construct", ReflectConstruct,
   "enumerate", ReflectEnumerate
 ]);
 
 })