// Copyright 2017 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.assertTrue(Symbol.hasOwnProperty('asyncIterator'));assertEquals('symbol',typeofSymbol.asyncIterator);assertInstanceof(Object(Symbol.asyncIterator),Symbol);letdesc=Object.getOwnPropertyDescriptor(Symbol,'asyncIterator');assertFalse(desc.writable);assertFalse(desc.enumerable);assertFalse(desc.configurable);