Close receivePort when tests are failing.

pkg/unittest/lib/src/config.dart

Index: pkg/unittest/lib/src/config.dart
diff --git a/pkg/unittest/lib/src/config.dart b/pkg/unittest/lib/src/config.dart
index f0cf526e882baff7b58aebc114a0d545c795076f..e3a788ea1536867de559c512678b34b3391f6b5d 100644
--- a/pkg/unittest/lib/src/config.dart
+++ b/pkg/unittest/lib/src/config.dart
@@ -129,9 +129,9 @@ class Configuration {
       print('$passed PASSED, $failed FAILED, $errors ERRORS');
     }
 
+    _receivePort.close();
     if (success) {
       _postMessage('unittest-suite-success');
-      _receivePort.close();
     } else {
       throw new Exception('Some tests failed.');
     }