Start cleaning up the HTML tests.

pkg/dev_compiler/test/codegen/lib/html/domparser_test.dart

-library DOMParserTest;
-import 'package:unittest/unittest.dart';
-import 'package:unittest/html_config.dart';
 import 'dart:html';
 
+import 'package:minitest/minitest.dart';
+
 main() {
-
-  useHtmlConfiguration();
-
   var isDomParser = predicate((x) => x is DomParser, 'is a DomParser');
 
   test('constructorTest', () {
-      var ctx = new DomParser();
-      expect(ctx, isNotNull);
-      expect(ctx, isDomParser);
+    var ctx = new DomParser();
+    expect(ctx, isNotNull);
+    expect(ctx, isDomParser);
   });
 }