Format all tests.

tests/html/custom/document_register_template_test.dart

 import 'package:unittest/unittest.dart';
 import 'package:unittest/html_config.dart';
 import 'dart:html';
 import '../utils.dart';
 
 main() {
   useHtmlConfiguration();
 
   setUp(() => customElementsReady);
 
   test('can register custom template with webcomponents-lite polyfill', () {
     document.registerElement('my-element', MyElement, extendsTag: 'template');
     var e = new Element.tag('template', 'my-element');
     document.body.append(e);
     expect(e is TemplateElement, isTrue);
     expect(e.method(), 'value');
   });
 }
 
-
 class MyElement extends TemplateElement {
   MyElement.created() : super.created();
   method() => 'value';
 }