Update unittest to new package layout.

tests/html/blob_constructor_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('blob_test');
-#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');
 
 main() {
   useHtmlConfiguration();
 
   test('basic', () {
       var b = new Blob([]);
       expect(b.size, 0);
     });
 
@@ skipping 30 matching lines @@
       expect(b1.size, 1);
       expect(b2.size, 2);
     });
 
   test('fromArrayBuffer', () {
       var a = new Uint8Array(100).buffer; // i.e. new ArrayBuffer(100);
       var b = new Blob([a, a]);
       expect(b.size, 200);
     });
 }