Allow 'empty' tests if a feature is not supported in the browser.

pkg/unittest/lib/html_individual_config.dart

Index: pkg/unittest/lib/html_individual_config.dart
diff --git a/pkg/unittest/lib/html_individual_config.dart b/pkg/unittest/lib/html_individual_config.dart
index cf803cd4ba836823a5b06422c74d26740a7f1aad..a031b783c79cd3da8e52da42ce31bc2fe43beadf 100644
--- a/pkg/unittest/lib/html_individual_config.dart
+++ b/pkg/unittest/lib/html_individual_config.dart
@@ -37,11 +37,6 @@ class HtmlIndividualConfiguration extends htmlconfig.HtmlConfiguration {
         var startsWith = "$testGroupName${unittest.groupSep}";
         unittest.filterTests((unittest.TestCase tc) =>
             tc.description.startsWith(startsWith));
-
-
-        /*if(unittest.testCases.isEmpty) {
-          throw 'No tests match group "$testGroupName".';
-        }*/
       }
     }
     super.onStart();