Array.prototype.map write error.

test/mjsunit/regress/regress-716044.js

+// 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.
+
+// Flags: --verify-heap
+
+class Array1 extends Array {
+  constructor(len) {
+      super(1);
+    }
+};
+
+class MyArray extends Array {
+  static get [Symbol.species]() {
+      return Array1;
+    }
+}
+
+a = new MyArray();
+
+for (var i = 0; i < 100000; i++) {
+  a.push(1);
+}
+
+a.map(function(x) { return 42; });