Update unittest to new package layout.

tests/html/dom_isolates_test.dart

 // Copyright (c) 2012, 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('DOMIsolatesTest');
-#import('../../pkg/unittest/unittest.dart');
-#import('../../pkg/unittest/html_config.dart');
+#import('../../pkg/unittest/lib/unittest.dart');
+#import('../../pkg/unittest/lib/html_config.dart');
 #import('dart:html');
 #import('dart:isolate');
 
 isolateMain() {
   port.receive((msg, replyTo) {
     if (msg != 'check') {
       replyTo.send('wrong msg: $msg');
     }
     replyTo.send('${window.location}');
     port.close();
@@ skipping 37 matching lines @@
     var closure = guardAsync(() {});
     expect(() => spawnDomFunction(closure), throws);
   });
 
   test('Masked local function', () {
     var local = 42;
     dummy() => print("Bad invocation of local function: $local");
     expect(() => spawnDomFunction(dummy), throws);
   });
 }