Enable strict flags for all service tests

runtime/observatory/test/metrics_test.dart

 // 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/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
 
 import 'dart:profiler';
 
 void script() {
   var counter = new Counter('a.b.c', 'description');
   Metrics.register(counter);
@@ skipping 18 matching lines @@
   }),
 
 (Isolate isolate) =>
   isolate.invokeRpc('getIsolateMetric', { 'metricId': 'metrics/a.b.d' })
       .then((DartError err) {
     expect(err is DartError, isTrue);
   }),
 ];
 
 main(args) => runIsolateTests(args, tests, testeeBefore: script);