Add all dart:html tests from the sdk to test/codegen.

test/codegen/lib/html/xsltprocessor_test.dart

+library XSLTProcessorTest;
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_individual_config.dart';
+import 'dart:html';
+
+main() {
+
+  useHtmlIndividualConfiguration();
+
+  group('supported', () {
+    test('supported', () {
+      expect(XsltProcessor.supported, true);
+    });
+  });
+
+  group('functional', () {
+    var isXsltProcessor =
+      predicate((x) => x is XsltProcessor, 'is an XsltProcessor');
+
+    var expectation = XsltProcessor.supported ? returnsNormally : throws;
+
+    test('constructorTest', () {
+      expect(() {
+        var processor = new XsltProcessor();
+        expect(processor, isNotNull);
+        expect(processor, isXsltProcessor);
+      }, expectation);
+    });
+  });
+
+}