catchErrors and waitForCompletion now based on runZonedExperimental.

tests/lib/async/run_zoned7_test.dart

Index: tests/lib/async/run_zoned7_test.dart
diff --git a/tests/lib/async/catch_errors28_test.dart b/tests/lib/async/run_zoned7_test.dart
similarity index 85%
copy from tests/lib/async/catch_errors28_test.dart
copy to tests/lib/async/run_zoned7_test.dart
index a5ce19e1270c89291333580070da82118a7f13b2..3bd3dbbbec9f0ec869c9f2ca77a11f824c079c6f 100644
--- a/tests/lib/async/catch_errors28_test.dart
+++ b/tests/lib/async/run_zoned7_test.dart
@@ -5,24 +5,22 @@
 import "package:expect/expect.dart";
 import 'dart:async';
 import 'dart:isolate';
+import 'catch_errors.dart';
 
 main() {
   // We keep a ReceivePort open until all tests are done. This way the VM will
   // hang if the callbacks are not invoked and the test will time out.
   var port = new ReceivePort();
   var events = [];
-  // Test that periodic Timers are handled correctly by `catchErrors`.
-  catchErrors(() {
+  // Test runZoned with periodic Timers.
+  runZonedExperimental(() {
     int counter = 0;
     new Timer.periodic(const Duration(milliseconds: 50), (timer) {
       if (counter == 5) timer.cancel();
       counter++;
       events.add(counter);
     });
-  }).listen((x) {
-      events.add(x);
-    },
-    onDone: () {
+  }, onDone: () {
       Expect.listEquals([
                          "main exit",
                          1, 2, 3, 4, 5, 6,