remove unused code

Former-commit-id: 7ebbaeb25d5bd40b0d028a035eafe096d8ca20c9

core/src/scheduler/task/SearchTask.cpp

@@ -204,11 +204,6 @@ XSearchTask::Execute() {
         output_distance.resize(topk * nq);
         std::string hdr =
             "job " + std::to_string(search_job->id()) + " nq " + std::to_string(nq) + " topk " + std::to_string(topk);
-        auto str = R"(s324gagbds
-bbvcb\fds
-b
-fdb\f
-e))";
 
         try {
             // step 2: search