Format all tests.

tests/lib/async/stack_trace12_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:expect/expect.dart';
 import 'package:async_helper/async_helper.dart';
 import 'dart:async';
 
 main() {
   StackTrace trace;
   asyncStart();
-  var f = new Future(() { throw "foo"; });
-  f.then((_) { throw "Unreachable"; },
-    onError: (e, st) {
-      Expect.equals("foo", e);
-      Expect.isNotNull(st);
-      asyncEnd();
-    });
+  var f = new Future(() {
+    throw "foo";
+  });
+  f.then((_) {
+    throw "Unreachable";
+  }, onError: (e, st) {
+    Expect.equals("foo", e);
+    Expect.isNotNull(st);
+    asyncEnd();
+  });
 }