Bump wait time for watcher test.

pkg/watcher/test/no_subscription_test.dart

 // Copyright (c) 2012, 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.
 
 import 'dart:async';
 
 import 'package:scheduled_test/scheduled_test.dart';
 import 'package:watcher/watcher.dart';
 
 import 'utils.dart';
@@ skipping 39 matching lines @@
         expect(event.type, equals(ChangeType.ADD));
         expect(event.path, endsWith("added.txt"));
         completer.complete();
       }));
     });
 
     // The watcher will have been cancelled and then resumed in the middle of
     // its pause between polling loops. That means the second scan to skip
     // what changed while we were unsubscribed won't happen until after that
     // delay is done. Wait long enough for that to happen.
-    schedule(() => new Future.delayed(watcher.pollingDelay * 2));
+    //
+    // We're doing * 4 here because that seems to give the slower bots enough
+    // time for this to complete.
+    schedule(() => new Future.delayed(watcher.pollingDelay * 4));
 
     // And add a third file.
     writeFile("added.txt");
 
     // Wait until we get an event for the third file.
     schedule(() => completer.future);
 
     schedule(() {
       subscription.cancel();
     });
   });
 }