Refactoring to allow html_individual_config to pass with zero tests executed.

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 1c1d11e1e9d316b8ff27c8a4bbbdfac9df95efda..f9e7333744f2737b703f6ffdb4cac5840713380e 100644
--- a/pkg/unittest/lib/html_individual_config.dart
+++ b/pkg/unittest/lib/html_individual_config.dart
@@ -41,6 +41,21 @@ class HtmlIndividualConfiguration extends htmlconfig.HtmlConfiguration {
     }
     super.onStart();
   }
+
+  bool _failedOrErrors = false;
+  void onSummary(int passed, int failed, int errors, List<TestCase> results,
+      String uncaughtError) {
+    super.onSummary(passed, failed, errors, results, uncaughtError);
+
+    _failedOrErrors = failed > 0 || errors > 0;
+  }
+
+  void onDone(bool success) {
+    if (!success) {
+      success = !_failedOrErrors;
+    }
+    super.onDone(success);
+  }
 }
 
 void useHtmlIndividualConfiguration([bool isLayoutTest = false]) {