Update unittest to new package layout.

tests/benchmark_smoke/benchmark_smoke_test.dart

 // Copyright (c) 2011, 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.
 #library('benchmark_smoke_test');
 
 // Tests that benchmark classes used in perf testing are not broken.
 #import('benchmark_lib.dart');
 #import('dart:html');
-#import('../../pkg/unittest/unittest.dart');
-#import('../../pkg/unittest/html_config.dart');
+#import('../../pkg/unittest/lib/unittest.dart');
+#import('../../pkg/unittest/lib/html_config.dart');
 
 void main() {
   useHtmlConfiguration();
 
-  test('performanceTesting', () { 
+  test('performanceTesting', () {
     window.setTimeout(BENCHMARK_SUITE.runBenchmarks, 0);
     window.setTimeout(expectAsync0(testForCompletion), 0);
   });
 }
 
 testForCompletion() {
   Element element = document.query('#testResultScore');
   RegExp re = new RegExp('Score: [0-9]+');
   print(element.text);
   Expect.isTrue(re.hasMatch(element.text));
 }