Remove some more library directives

pkg/analysis_server/benchmark/perf/benchmark_scenario.dart

Index: pkg/analysis_server/benchmark/perf/benchmark_scenario.dart
diff --git a/pkg/analysis_server/benchmark/perf/benchmark_scenario.dart b/pkg/analysis_server/benchmark/perf/benchmark_scenario.dart
index fc0681f89fd046b4db242b96ab5a0644b2898550..930bc0e7cd3c943dca1327229ab1959dcdae423d 100644
--- a/pkg/analysis_server/benchmark/perf/benchmark_scenario.dart
+++ b/pkg/analysis_server/benchmark/perf/benchmark_scenario.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.scenarios;
-
 import 'dart:async';
 import 'dart:io';
 import 'dart:math';