[es6] Function.prototype.name should be the empty string

test/mjsunit/es6/function-name-configurable.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.
 
 function getStrictF() {
   'use strict';
   return function f() {};
 }
 
 
@@ skipping 72 matching lines @@
 }
 test(testFunctionToString);
 
 
 (function testSetOnInstance() {
   // This needs to come before testDelete below
   assertTrue(Function.prototype.hasOwnProperty('name'));
 
   function f() {}
   delete f.name;
-  assertEquals('Empty', f.name);
+  assertEquals('', f.name);
 
   f.name = 42;
-  assertEquals('Empty', f.name);  // non writable prototype property.
+  assertEquals('', f.name);  // non writable prototype property.
   assertFalse(f.hasOwnProperty('name'));
 
   Object.defineProperty(Function.prototype, 'name', {writable: true});
 
   f.name = 123;
   assertTrue(f.hasOwnProperty('name'));
   assertEquals(123, f.name);
 })();
 
 
 (function testDelete() {
   function f() {}
   assertTrue(delete f.name);
   assertFalse(f.hasOwnProperty('name'));
-  assertEquals('Empty', f.name);
+  assertEquals('', f.name);
 
   assertTrue(delete Function.prototype.name);
   assertEquals(undefined, f.name);
 })();