Redo StreamTransformers so they work with Stack traces.

tests/lib/async/catch_errors27_test.dart

Index: tests/lib/async/catch_errors27_test.dart
diff --git a/tests/lib/async/catch_errors27_test.dart b/tests/lib/async/catch_errors27_test.dart
index ab89f16b113a7937e7797f24d1ecff0a0f3ec1ad..9a1f0d7dda8f668494763de48a2244d222d4ae0f 100644
--- a/tests/lib/async/catch_errors27_test.dart
+++ b/tests/lib/async/catch_errors27_test.dart
@@ -28,8 +28,8 @@ main() {
         })
         .asBroadcastStream();
       stream
-        .transform(new StreamTransformer(
-            handleError: (e, sink) => sink.add("error $e")))
+        .transform(new StreamTransformer.fromHandlers(
+            handleError: (e, st, sink) => sink.add("error $e")))
         .listen((x) { events.add("stream $x"); });
       runAsync(() {
         controller.add(1);