Migrate async tests to strong

tests/lib_strong/async/catch_errors22_test.dart

+// Copyright (c) 2013, 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 'package:async_helper/async_helper.dart';
+import "package:expect/expect.dart";
+import 'dart:async';
+import 'catch_errors.dart';
+
+main() {
+  asyncStart();
+
+  var events = [];
+  bool onDoneWasCalled = false;
+  var controller = new StreamController();
+  // Test that streams that are never closed keep the `catchError` alive.
+  catchErrors(() {
+    catchErrors(() {
+      controller.stream.map((x) { throw x; }).listen((x) {
+        // Should not happen.
+        events.add("bad: $x");
+      });
+    }).listen((x) { events.add("caught: $x"); },
+              onDone: () { events.add("done"); });
+  }).listen((x) { events.add("outer: $x"); },
+            onDone: () { onDoneWasCalled = true; });
+
+  [1, 2, 3, 4].forEach(controller.add);
+
+  new Timer(const Duration(milliseconds: 20), () {
+    Expect.isFalse(onDoneWasCalled);
+    Expect.listEquals(["caught: 1",
+                       "caught: 2",
+                       "caught: 3",
+                       "caught: 4",
+                      ],
+                      events);
+    asyncEnd();
+  });
+}