Add back previously removed tests

pkg/analysis_server/lib/src/analysis_server.dart

 // Copyright (c) 2014, 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 analysis.server;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/analysis_logger.dart';
 import 'package:analysis_server/src/channel.dart';
@@ skipping 144 matching lines @@
     }
   }
 
   /**
    * Perform the tasks that are waiting for execution until the server is shut
    * down.
    */
   void run() {
     if (!running) {
       running = true;
-      Timer.run(() {
-        performTask();
+      new Future(performTask).catchError((exception, stackTrace) {
+        AnalysisEngine.instance.logger.logError3(exception);
       });
     }
   }
 
   /**
    * Send the given [notification] to the client.
    */
   void sendNotification(Notification notification) {
     channel.sendNotification(notification);
   }
 }