Get rid of all the library tags.

lib/src/executable.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.
 
 // TODO(nweiz): This is under lib so that it can be used by the unittest dummy
 // package. Once that package is no longer being updated, move this back into
 // bin.
-library test.executable;
-
 import 'dart:io';
 
 import 'package:stack_trace/stack_trace.dart';
 import 'package:yaml/yaml.dart';
 
 import 'runner.dart';
 import 'runner/application_exception.dart';
 import 'runner/configuration.dart';
 import 'runner/version.dart';
 import 'util/exit_codes.dart' as exit_codes;
@@ skipping 131 matching lines @@
     output = stderr;
   }
 
   output.write("""$message
 
 Usage: pub run test:test [files or directories...]
 
 ${Configuration.usage}
 """);
 }