Increase delay when after eventually consistent operations in datastore/storage

test/datastore/e2e/datastore_test_impl.dart

Index: test/datastore/e2e/datastore_test_impl.dart
diff --git a/test/datastore/e2e/datastore_test_impl.dart b/test/datastore/e2e/datastore_test_impl.dart
index ef550662cf9cef89363c7df2b0e5980bd9ccc376..685840f3da776e38c98d6f2b354815a0cb871323 100644
--- a/test/datastore/e2e/datastore_test_impl.dart
+++ b/test/datastore/e2e/datastore_test_impl.dart
@@ -39,14 +39,6 @@ import 'utils.dart';
 
 import '../../common_e2e.dart';
 
-// Note:
-// Non-ancestor queries (i.e. queries not lookups) result in index scans.
-// The index tables are updated in a "eventually consistent" way.
-//
-// So this can make tests flaky, the index updates take longer than the
-// following constant.
-const INDEX_UPDATE_DELAY = const Duration(seconds: 10);
-
 Future sleep(Duration duration) {
   var completer = new Completer();
   new Timer(duration, completer.complete);