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

test/codegen/lib/html/location_test.dart

+library LocationTest;
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+import 'dart:html';
+
+main() {
+  useHtmlConfiguration();
+
+  var isLocation = predicate((x) => x is Location, 'is a Location');
+
+  test('location hash', () {
+      final location = window.location;
+      expect(location, isLocation);
+
+      // The only navigation we dare try is hash.
+      location.hash = 'hello';
+      var h = location.hash;
+      expect(h, '#hello');
+    });
+
+  test('location.origin', () {
+    var origin = window.location.origin;
+
+    // We build up the origin from Uri, then make sure that it matches.
+    var uri = Uri.parse(window.location.href);
+    var reconstructedOrigin = '${uri.scheme}://${uri.host}';
+    if (uri.port != 0) {
+      reconstructedOrigin = '$reconstructedOrigin:${uri.port}';
+    }
+
+    expect(origin, reconstructedOrigin);
+  });
+}