Enable strict flags for all service tests

runtime/observatory/test/dominator_tree_test.dart

Index: runtime/observatory/test/dominator_tree_test.dart
diff --git a/runtime/observatory/test/dominator_tree_test.dart b/runtime/observatory/test/dominator_tree_test.dart
index 0bd52b3a4f59a0cc53b9576c5cf3efb8bfc40f41..6db7b3c95bdaffa056e08439c996afe032e4e039 100644
--- a/runtime/observatory/test/dominator_tree_test.dart
+++ b/runtime/observatory/test/dominator_tree_test.dart
@@ -1,6 +1,7 @@
 // Copyright (c) 2014, 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.
+// VMOptions=--compile-all --error_on_bad_type --error_on_bad_override --checked
 
 import 'package:observatory/dominator_tree.dart';
 import 'package:unittest/unittest.dart';
@@ -39,7 +40,7 @@ void smallTest() {
   expect(d.dominator('A'), equals('R'));
   expect(d.dominator('D'), equals('R'));
   expect(d.dominator('B'), equals('R'));
-  
+
   expect(d.dominator('F'), equals('C'));
   expect(d.dominator('G'), equals('C'));
   expect(d.dominator('J'), equals('G'));