Fix analyzer hints and warnings in test/.

test/run/doesnt_load_an_unnecessary_transformer_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.
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
-import '../serve/utils.dart';
 
 const TRANSFORMER = """
 import 'dart:async';
 
 import 'package:barback/barback.dart';
 
 class BrokenTransformer extends Transformer {
   RewriteTransformer.asPlugin() {
     throw 'This transformer is broken!';
   }
@@ skipping 28 matching lines @@
      pubGet();
 
      // This shouldn't load the transformer, since it doesn't transform
      // anything that the entrypoint imports. If it did load the transformer,
      // we'd know since it would throw an exception.
      var pub = pubRun(args: ["bin/hi"]);
      pub.stdout.expect("Hello!");
      pub.shouldExit();
    });
 }