add performance tests

pkg/analysis_server/test/integration/integration_tests.dart

Index: pkg/analysis_server/test/integration/integration_tests.dart
diff --git a/pkg/analysis_server/test/integration/integration_tests.dart b/pkg/analysis_server/test/integration/integration_tests.dart
index 08fb56d02234d4b67b2697f29549d6e479f0dad9..ed2d62af2dcf1a44e56ffe4ca7293f40c2fa1bc5 100644
--- a/pkg/analysis_server/test/integration/integration_tests.dart
+++ b/pkg/analysis_server/test/integration/integration_tests.dart
@@ -197,7 +197,7 @@ abstract class AbstractAnalysisServerIntegrationTest
    * After every test, the server is stopped and [sourceDirectory] is deleted.
    */
   Future tearDown() {
-    return _shutdownIfNeeded().then((_) {
+    return shutdownIfNeeded().then((_) {
       sourceDirectory.deleteSync(recursive: true);
     });
   }
@@ -222,7 +222,7 @@ abstract class AbstractAnalysisServerIntegrationTest
   /**
    * If [skipShutdown] is not set, shut down the server.
    */
-  Future _shutdownIfNeeded() {
+  Future shutdownIfNeeded() {
     if (skipShutdown) {
       return new Future.value();
     }