Minor observatory test cleanups.

runtime/observatory/tests/service/pause_on_start_then_step_test.dart

Index: runtime/observatory/tests/service/pause_on_start_then_step_test.dart
diff --git a/runtime/observatory/tests/service/pause_on_start_then_step_test.dart b/runtime/observatory/tests/service/pause_on_start_then_step_test.dart
index 2c7b3b6ffc16e15c292595aeb73ef222c28c626b..20e91c5a196270e907a80145d882c8fb561104bf 100644
--- a/runtime/observatory/tests/service/pause_on_start_then_step_test.dart
+++ b/runtime/observatory/tests/service/pause_on_start_then_step_test.dart
@@ -1,10 +1,9 @@
 // Copyright (c) 2015, 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
+// VMOptions=--error_on_bad_type --error_on_bad_override
 
 import 'package:observatory/service_io.dart';
-import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
 import 'dart:async';