unittest step2: bye bye to multiple entrypoints for unittest

client/tests/client/dom/TypingTest.dart

 #library('TypingTest');
-#import('../../../../lib/unittest/unittest_dom.dart');
+#import('../../../../lib/unittest/unittest.dart');
+#import('../../../../lib/unittest/dom_config.dart');
 #import('dart:dom');
 
 main() {
-  forLayoutTests();
+  useDomConfiguration();
 
   test('NodeList', () {
     List<Node> asList = window.document.getElementsByTagName('body');
     // Check it's Iterable
     int counter = 0;
     for (Node node in window.document.getElementsByTagName('body')) {
       counter++;
     }
     Expect.equals(1, counter);
     counter = 0;
     window.document.getElementsByTagName('body').forEach((e) { counter++; });
     Expect.equals(1, counter);
   });
 
   test('StyleSheetList', () {
     List<StyleSheet> asList = window.document.styleSheets;
     // Check it's Iterable.
     int counter = 0;
     for (StyleSheet styleSheet in window.document.styleSheets) {
       counter++;
     }
 
     // There is one style sheet from the unittest framework.
     Expect.equals(1, counter);
   });
 }