Map.prototype descriptor

test/built-ins/Map/prototype/descriptor.js

+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 23.1.2.1
+description: Map.prototype property attributes.
+info: >
+  This property has the attributes { [[Writable]]: false, [[Enumerable]]: false,
+  [[Configurable]]: false }.
+includes: [propertyHelper.js]
+---*/
+
+verifyNotEnumerable(Map, 'prototype');
+verifyNotWritable(Map, 'prototype');
+verifyNotConfigurable(Map, 'prototype');