Migrated test block 170 to Dart 2.0.

tests/lib_2/async/intercept_print1_test.dart

 // Copyright (c) 2013, 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.
 
 import "package:expect/expect.dart";
 import 'dart:async';
 import 'catch_errors.dart';
 
 var events = [];
 
@@ skipping 26 matching lines @@
   });
   zone2.run(() {
     print("5");
     shouldIntercept = false;
     print(6);
   });
   Expect.listEquals(
       ["print: 1", "print: 2", "print: {3: [4]}", "print **: 5", "print: 6"],
       events);
 }