Fix analyzer hints and warnings in test/.

test/run/runs_from_a_dependency_override_after_dependency_test.dart

 // 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.
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
-import '../serve/utils.dart';
 
 main() {
   // Regression test for issue 23113
   integration('runs a named Dart application in a dependency', () {
     servePackages((builder) {
       builder.serve('foo', '1.0.0', pubspec: {
         'name': 'foo',
         'version': '1.0.0'
       }, contents: [
         d.dir("bin", [
@@ skipping 26 matching lines @@
       })
     ]).create();
 
     pubGet();
 
     pub = pubRun(args: ["foo:bar"]);
     pub.stdout.expect("different");
     pub.shouldExit();
   });
 }