Use "package:" imports for pub.

test/lish/server_arg_does_not_override_private_test.dart

Index: test/lish/server_arg_does_not_override_private_test.dart
diff --git a/test/lish/server_arg_does_not_override_private_test.dart b/test/lish/server_arg_does_not_override_private_test.dart
index 5be6bfc86a5369978ef0cf0d03adff2f13a7d642..8d33c82378eb6923875afbaea5f9cc977ebebef9 100644
--- a/test/lish/server_arg_does_not_override_private_test.dart
+++ b/test/lish/server_arg_does_not_override_private_test.dart
@@ -2,9 +2,9 @@
 // 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:pub/src/exit_codes.dart' as exit_codes;
 import 'package:scheduled_test/scheduled_test.dart';
 
-import '../../lib/src/exit_codes.dart' as exit_codes;
 import '../descriptor.dart' as d;
 import '../test_pub.dart';