Beef up analysis server integration test messages.

pkg/analysis_server/benchmark/integration/driver.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.driver;
 
 import 'dart:async';
 import 'dart:math' show max, sqrt;
 
 import 'package:logging/logging.dart';
@@ skipping 116 matching lines @@
   /**
    * Shutdown the analysis server if it is running.
    */
   Future stopServer([Duration timeout = SHUTDOWN_TIMEOUT]) async {
     if (running) {
       logger.log(Level.FINE, 'requesting server shutdown');
       // Give the server a short time to comply with the shutdown request; if it
       // doesn't exit, then forcibly terminate it.
       sendServerShutdown();
       await server.exitCode.timeout(timeout, onTimeout: () {
-        return server.kill();
+        return server.kill('server failed to exit');
       });
     }
     _resultsReady();
   }
 
   /**
    * If not already complete, signal the completer with the collected results.
    */
   void _resultsReady() {
     if (!_runCompleter.isCompleted) {
@@ skipping 159 matching lines @@
       int totalUnexpectedResultCount) {
     StringBuffer sb = new StringBuffer();
     _printColumn(sb, 'Totals', keyLen);
     _printColumn(sb, totalCount.toString(), 6, rightJustified: true);
     _printColumn(sb, totalErrorCount.toString(), 6, rightJustified: true);
     _printColumn(sb, totalUnexpectedResultCount.toString(), 6,
         rightJustified: true);
     print(sb.toString());
   }
 }