Copy lib/dom tests that use dart:html to lib/html.

tests/html/native_gc_test.dart

 #library('NativeGCTest');
 #import('../../lib/unittest/unittest.dart');
 #import('../../lib/unittest/html_config.dart');
 #import('dart:html');
 
 main() {
   useHtmlConfiguration();
 
   test('EventListener', () {
       final int N = 1000000;
@@ skipping 13 matching lines @@
             // Only the final iteration's listener should be invoked.
             // Note: the reference to l keeps the entire list alive.
             Expect.equals(M - 1, l[N - 1]);
           }, false);
       }
 
       final event = new Event('test');
       div.on['test'].dispatch(event);
   });
 }