unittest step2: bye bye to multiple entrypoints for unittest

client/tests/client/dom/HTMLCollectionTest.dart

 #library('HTMLCollectionTest');
-#import('../../../../lib/unittest/unittest_dom.dart');
+#import('../../../../lib/unittest/unittest.dart');
+#import('../../../../lib/unittest/dom_config.dart');
 #import('dart:dom');
 
 // Test that HTMLCollection implements List<T>
 main() {
   HTMLElement insertTestDiv() {
     HTMLElement element = document.createElement('div');
     element.innerHTML = @"""
 <div id='allChecked'>
 <input type="checkbox" name="c1" value="1" checked="yes">
 <input type="checkbox" name="c2" value="2" checked="yes">
@@ skipping 11 matching lines @@
 <input type="checkbox" name="n2" value="2">
 <input type="checkbox" name="n3" value="3">
 <input type="checkbox" name="n4" value="4">
 </div>
 <div id='emptyDiv'></div>
 """;
     document.body.appendChild(element);
     return element;
   }
 
-  forLayoutTests();
+  useDomConfiguration();
   test('IsList', () {
     HTMLElement root = insertTestDiv();
 
     HTMLCollection eachChecked =
         document.getElementById('allChecked').dynamic.children;
 
     Expect.isTrue(eachChecked is List);
 
     document.body.removeChild(root);
   });
@@ skipping 222 matching lines @@
     Expect.equals(-1, someChecked.lastIndexOf(someChecked[3], 2));
 
     Expect.equals(-1, someChecked.lastIndexOf(noneChecked[0], 3));
     Expect.equals(-1, noneChecked.lastIndexOf(someChecked[0], 3));
     Expect.equals(-1, someChecked.lastIndexOf(noneChecked[1], 3));
     Expect.equals(-1, noneChecked.lastIndexOf(someChecked[1], 3));
 
     document.body.removeChild(root);
   });
 }