Get rid of all the library tags.

lib/src/backend/invoker.dart

 // Copyright (c) 2015, 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.
 
-library test.backend.invoker;
-
 import 'dart:async';
 
 import 'package:stack_trace/stack_trace.dart';
 
 import '../backend/group.dart';
 import '../frontend/expect.dart';
 import '../utils.dart';
 import 'closed_exception.dart';
 import 'live_test.dart';
 import 'live_test_controller.dart';
@@ skipping 261 matching lines @@
         // outstanding callback counters at once.
         _counterKey: outstandingCallbacksForBody,
         _closableKey: true
       },
           zoneSpecification: new ZoneSpecification(
               print: (self, parent, zone, line) => _controller.print(line)),
           onError: _handleError);
     });
   }
 }