Enable strict flags for all service tests

runtime/observatory/test/test_helper.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.
+// VMOptions=--compile-all --error_on_bad_type --error_on_bad_override --checked
 
 library test_helper;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'package:unittest/unittest.dart';
 import 'package:observatory/service_io.dart';
 
 // This invocation should set up the state being tested.
@@ skipping 144 matching lines @@
       var name = Platform.script.pathSegments.last;
       new WebSocketVM(new WebSocketVMTarget(addr)).load()
           .then((VM vm) => Future.forEach(tests, (test) {
             print('Running $name [$testIndex/$totalTests]');
             testIndex++;
             return test(vm);
           })).then((_) => exit(0));
     });
   }
 }