[es6] Map/Set size getter should have "get size" name

test/mjsunit/es6/collections.js

 // Copyright 2012 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 425 matching lines @@
 
 
 // Set and Map size getters
 var setSizeDescriptor = Object.getOwnPropertyDescriptor(Set.prototype, 'size');
 assertEquals(undefined, setSizeDescriptor.value);
 assertEquals(undefined, setSizeDescriptor.set);
 assertTrue(setSizeDescriptor.get instanceof Function);
 assertEquals(undefined, setSizeDescriptor.get.prototype);
 assertFalse(setSizeDescriptor.enumerable);
 assertTrue(setSizeDescriptor.configurable);
+assertEquals('get size', setSizeDescriptor.get.name);
 
 var s = new Set();
 assertFalse(s.hasOwnProperty('size'));
 for (var i = 0; i < 10; i++) {
   assertEquals(i, s.size);
   s.add(i);
 }
 for (var i = 9; i >= 0; i--) {
   s.delete(i);
   assertEquals(i, s.size);
 }
 
 
 var mapSizeDescriptor = Object.getOwnPropertyDescriptor(Map.prototype, 'size');
 assertEquals(undefined, mapSizeDescriptor.value);
 assertEquals(undefined, mapSizeDescriptor.set);
 assertTrue(mapSizeDescriptor.get instanceof Function);
 assertEquals(undefined, mapSizeDescriptor.get.prototype);
 assertFalse(mapSizeDescriptor.enumerable);
 assertTrue(mapSizeDescriptor.configurable);
+assertEquals('get size', mapSizeDescriptor.get.name);
 
 var m = new Map();
 assertFalse(m.hasOwnProperty('size'));
 for (var i = 0; i < 10; i++) {
   assertEquals(i, m.size);
   m.set(i, i);
 }
 for (var i = 9; i >= 0; i--) {
   m.delete(i);
   assertEquals(i, m.size);
@@ skipping 991 matching lines @@
   assertEquals(adderName + 'iterator', log);
 
   Object.defineProperty(ctor.prototype, adderName, {
     value: adderFunction
   });
 }
 TestConstructorOrderOfAdderIterator(Map, 'set');
 TestConstructorOrderOfAdderIterator(Set, 'add');
 TestConstructorOrderOfAdderIterator(WeakMap, 'set');
 TestConstructorOrderOfAdderIterator(WeakSet, 'add');