[UT] Fix bug for cache unit test (#5766)

For #5726 . Last commit is not logic perfect, which will cause some unit tests not passed.

be/src/runtime/cache/result_cache.cpp

@@ -140,7 +140,7 @@ void ResultCache::fetch(const PFetchCacheRequest* request, PFetchCacheResult* re
                 break;
             }
         }
-        if (part_rowbatch_list.empty()) {
+        if (status == PCacheStatus::CACHE_OK && part_rowbatch_list.empty()) {
             status = PCacheStatus::EMPTY_DATA;
         }
         result->set_status(status);