Add a test of summaries that uses strong mode.

pkg/analyzer/test/src/summary/test_all.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 test.src.serialization.test_all;
 
 import 'package:unittest/unittest.dart';
 
 import '../../utils.dart';
 import 'flat_buffers_test.dart' as flat_buffers_test;
 import 'name_filter_test.dart' as name_filter_test;
 import 'prelinker_test.dart' as prelinker_test;
 import 'resynthesize_test.dart' as resynthesize_test;
 import 'summarize_ast_test.dart' as summarize_ast_test;
+import 'summarize_elements_strong_test.dart' as summarize_elements_strong_test;
 import 'summarize_elements_test.dart' as summarize_elements_test;
 
 /// Utility for manually running all tests.
 main() {
   initializeTestEnvironment();
   group('summary tests', () {
     flat_buffers_test.main();
     name_filter_test.main();
     prelinker_test.main();
     resynthesize_test.main();
     summarize_ast_test.main();
+    summarize_elements_strong_test.main();
     summarize_elements_test.main();
   });
 }