Remove uses of unittest in the HTML tests where possible.

pkg/dev_compiler/test/not_yet_strong_tests.dart

Index: pkg/dev_compiler/test/not_yet_strong_tests.dart
diff --git a/pkg/dev_compiler/test/not_yet_strong_tests.dart b/pkg/dev_compiler/test/not_yet_strong_tests.dart
index 7886944b18bd1b62fc18407ea4f3a3aa1617533b..14df23156fe4467610e8b4fd4f582d47f940cd48 100644
--- a/pkg/dev_compiler/test/not_yet_strong_tests.dart
+++ b/pkg/dev_compiler/test/not_yet_strong_tests.dart
@@ -2436,21 +2436,11 @@ final notYetStrongTests = new HashSet<String>.from([
   'lib/html/js_typed_interop_side_cast_exp_test',
   'lib/html/js_typed_interop_side_cast_test',
   'lib/html/keyboard_event_test',
-  'lib/html/localstorage_test',
   'lib/html/mutationobserver_test',
-  'lib/html/node_test',
-  'lib/html/node_validator_important_if_you_suppress_make_the_bug_critical_test',
   'lib/html/postmessage_structured_test',
-  'lib/html/queryall_test',
   'lib/html/resource_http_test',
-  'lib/html/selectelement_test',
-  'lib/html/track_element_constructor_test',
   'lib/html/transferables_test',
-  'lib/html/typed_arrays_range_checks_test',
-  'lib/html/typing_test',
-  'lib/html/unknownelement_test',
   'lib/html/webgl_1_test',
-  'lib/html/window_nosuchmethod_test',
   'lib/html/wrapping_collections_test',
   // TODO(jmesserly): these are both under "dart:html" as well.
   'js_test',