Add Zone support for Timers.

tests/lib/async/catch_errors3_test.dart

Index: tests/lib/async/catch_errors3_test.dart
diff --git a/tests/lib/async/catch_errors3_test.dart b/tests/lib/async/catch_errors3_test.dart
index 81dc7933570ac3773c25b4d826d1dd9617a681cd..16b0f5eb843980c40a266a04ecae3596d1bbeb12 100644
--- a/tests/lib/async/catch_errors3_test.dart
+++ b/tests/lib/async/catch_errors3_test.dart
@@ -8,7 +8,7 @@ import 'dart:isolate';
 
 main() {
   // We keep a ReceivePort open until all tests are done. This way the VM will
-  // time out if the callbacks are not invoked.
+  // hang if the callbacks are not invoked and the test will time out.
   var port = new ReceivePort();
   bool futureWasExecuted = false;
   bool future2WasExecuted = false;
@@ -26,7 +26,7 @@ main() {
     });
     return 'allDone';
   }).listen((x) {
-      Expect.fail("Unexped callback");
+      Expect.fail("Unexpected callback");
     },
     onDone: () {
       Expect.isTrue(futureWasExecuted);