Add missing parameter. (#4635)

Author: kaibolay

firebase-storage/src/testUtil/java/com/google/firebase/storage/TestUploadHelper.java

@@ -696,6 +696,7 @@ private static void verifyTaskCount(StorageReference reference, int expectedTask
         "Expected active upload task at location %s to contain %s item(s), "
             + "but contained %s item(s)",
         reference.getParent(),
+        expectedTasks,
         uploadTasksAtParent.size());
   }