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

tests/dom/exceptions_test.dart

-#library('ExceptionsTest');
-#import('../../lib/unittest/unittest.dart');
-#import('../../lib/unittest/html_config.dart');
-#import('dart:html');
-
-main() {
-  useHtmlConfiguration();
-  test('DOMException', () {
-    try {
-      window.webkitNotifications.createNotification('', '', '');
-    } catch (DOMException e) {
-      Expect.equals(DOMException.SECURITY_ERR, e.code);
-      Expect.equals('SECURITY_ERR', e.name);
-      Expect.equals('SECURITY_ERR: DOM Exception 18', e.message);
-    }
-  });
-  test('EventException', () {
-    final event = new Event('Event');
-    // Intentionally do not initialize it!
-    try {
-      document.$dom_dispatchEvent(event);
-    } catch (EventException e) {
-      Expect.equals(EventException.UNSPECIFIED_EVENT_TYPE_ERR, e.code);
-      Expect.equals('UNSPECIFIED_EVENT_TYPE_ERR', e.name);
-      Expect.equals('UNSPECIFIED_EVENT_TYPE_ERR: DOM Events Exception 0', e.message);
-    }
-  });
-}