Add another test for initializing dispatchPropertyName that runs outside the browser

tests/compiler/dart2js_native/dispatch_property_initialization_test.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test for initialization of dispatchPropertyName.
+
+import "package:expect/expect.dart";
+import 'dart:_foreign_helper' show JS;
+import 'dart:_js_helper' show Native;
+
+@Native("Foo")
+class Foo {
+  String method(String x) native;
+}
+
+makeFoo() native;
+
+void setup() native r"""
+function Foo() {}
+Foo.prototype.method = function(x) { return 'Foo ' + x; }
+
+self.makeFoo = function() { return new Foo(); }
+""";
+
+
+main() {
+  setup();
+
+  // If the dispatchPropertyName is uninitialized, it will be `undefined` or
+  // `null` instead of the secret string or Symbol. These properties on
+  // `Object.prototype` will be retrieved by the lookup instead of `undefined`
+  // for the dispatch record.
+  JS('', r'self.Object.prototype["undefined"] = {}');
+  JS('', r'self.Object.prototype["null"] = {}');
+  Expect.equals('Foo A', makeFoo().method('A'));
+
+  // Slightly different version that has malformed dispatch records.
+  JS('', r'self.Object.prototype["undefined"] = {p: false}');
+  JS('', r'self.Object.prototype["null"] = {p: false}');
+  Expect.equals('Foo B', makeFoo().method('B'));
+}