Remove some more library directives

pkg/analysis_server/benchmark/perf/performance_tests.dart

Index: pkg/analysis_server/benchmark/perf/performance_tests.dart
diff --git a/pkg/analysis_server/benchmark/perf/performance_tests.dart b/pkg/analysis_server/benchmark/perf/performance_tests.dart
index 236fd1a048e663e7fea06e1ce02ba1ebbe9edc20..540678ca65251ac95e40ced4104d948209f09dde 100644
--- a/pkg/analysis_server/benchmark/perf/performance_tests.dart
+++ b/pkg/analysis_server/benchmark/perf/performance_tests.dart
@@ -2,8 +2,6 @@
 // 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 server.performance;
-
 import 'dart:async';
 import 'dart:io';