triage remaining async tests

test/browser/language_tests.js

 // 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.
 
 (function() {
   'use strict';
 
   let _isolate_helper = dart_library.import('dart/_isolate_helper');
   _isolate_helper.startRootIsolate(function() {}, []);
   let async_helper = dart_library.import('async_helper/async_helper');
@@ skipping 52 matching lines @@
       'syncstar_yieldstar_test'
     ]);
   });
 
   dart_library.import('language/async_await_test').main();
 
   suite('async', () => {
     dartLanguageTests([
       'async_and_or_test',
       'async_await_catch_regression_test',
-      // TODO(jmesserly): fix errors
-      // 'async_backwards_compatibility_1_test',
+      'async_backwards_compatibility_1_test',
       'async_backwards_compatibility_2_test',
       'async_break_in_finally_test',
       // TODO(jmesserly): https://github.com/dart-lang/dev_compiler/issues/263
       // 'async_continue_label_test',
       'async_control_structures_test',
       'async_finally_rethrow_test',
-      // TODO(jmesserly): fix errors
-      // 'async_or_generator_return_type_stacktrace_test',
       'async_regression_23058_test',
       'async_rethrow_test',
-      // TODO(jmesserly): fix errors
-      // 'async_return_types_test',
       // TODO(jmesserly): https://github.com/dart-lang/dev_compiler/issues/294
       // 'async_switch_test',
       'async_test',
       'async_this_bound_test',
       'async_throw_in_catch_test'
+      // By design, rejected statically by strong mode:
+      // 'async_return_types_test',
+      // 'async_or_generator_return_type_stacktrace_test',
     ]);
   });
 
   dart_library.import('language/async_star_test_none_multi').main();
 
   suite('async*', () => {
     dartLanguageTests([
       // TODO(jmesserly): figure out why this test is hanging.
       //'async_star_cancel_and_throw_in_finally_test',
       'async_star_regression_23116_test',
@@ skipping 13 matching lines @@
       'export_main_override_test',
       'export_main_test',
       'export_test',
       'local_export_test',
       'reexport_core_test',
       'top_level_entry_test'
     ]);
   });
 
 })();