fix #28008, fix #28009 implement FutureOr<T>

tests/lib/async/future_or_bad_type_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.
 
 // In non strong-mode, `FutureOr<T>` is dynamic, even if `T` doesn't exist.
 // `FutureOr<T>` can not be used as superclass, mixin, nor can it be
 // implemented (as interface).
 
 import 'dart:async';
 import 'package:expect/expect.dart';
 
 class A
     extends FutureOr<String>  /// extends: compile-time error
     extends Object with FutureOr<bool>  /// with: compile-time error
     implements FutureOr<int>  /// implements: compile-time error
 {
 }
 
 main() {
   // FutureOr<T> should be treated like `dynamic`. Dynamically the `T` is
   // completely ignored. It can be a malformed type.
-  Expect.isTrue(499 is FutureOr<A>);  /// 00: static type warning
-  Expect.isTrue(499 is FutureOr<Does<Not<Exist>>>);  /// 01: static type warning
+  Expect.isTrue(499 is FutureOr<A>);
+  Expect.isTrue(499 is FutureOr<Does<Not<Exist>>>);  /// 00: static type warning
+  Expect.isTrue(499 is FutureOr<A, A>);              /// 01: static type warning
 
   var a = new A();
   Expect.isTrue(a.toString() is String);
 }