Get rid of all the library tags.

lib/src/backend/group_entry.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.group_entry;
-
 import 'metadata.dart';
 import 'operating_system.dart';
 import 'test.dart';
 import 'test_platform.dart';
 
 /// A [Test] or [Group].
 abstract class GroupEntry {
   /// The name of the entry, including the prefixes from any containing
   /// [Group]s.
   ///
@@ skipping 11 matching lines @@
   /// doesn't match.
   GroupEntry forPlatform(TestPlatform platform, {OperatingSystem os});
 
   /// Returns a copy of [this] with all tests that don't match [callback]
   /// removed.
   ///
   /// Returns `null` if this is a test that doesn't match [callback] or a group
   /// where no child tests match [callback].
   GroupEntry filter(bool callback(Test test));
 }