move performance measurement to benchmark/integration

pkg/analysis_server/benchmark/integration/operation.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.
 
 library server.operation;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:logging/logging.dart';
@@ skipping 218 matching lines @@
         subscription.cancel();
         timer.cancel();
         String message = 'gave up waiting for analysis to complete';
         driver.logger.log(Level.WARNING, message);
         completer.completeError(message);
       }
     });
     return completer.future;
   }
 }