test renaming overhaul: step 4 client tests

tests/dom/htmlelement_test.dart

 #library('HTMLElementTest');
-#import('../../../../lib/unittest/unittest.dart');
-#import('../../../../lib/unittest/dom_config.dart');
+#import('../../lib/unittest/unittest.dart');
+#import('../../lib/unittest/dom_config.dart');
 #import('dart:dom');
 
 main() {
   useDomConfiguration();
   test('InnerHTML', () {
     HTMLElement element = document.createElement('div');
     element.id = 'test';
     element.innerHTML = 'Hello World';
     document.body.appendChild(element);
 
@@ skipping 68 matching lines @@
 
     Expect.equals('foo-value', div.dataset.remove('foo'));
     Expect.equals(1, div.dataset.length);
     Expect.isFalse(div.dataset.isEmpty());
 
     div.dataset.clear();
     Expect.equals(0, div.dataset.length);
     Expect.isTrue(div.dataset.isEmpty());
   });
 }