[CP] Connect by with sys_connect_by_path if calc rescan return 4016.

src/sql/engine/connect_by/ob_cnnt_by_pump.cpp

@@ -85,10 +85,9 @@ void ObConnectByOpPump::reset()
     if (NULL != str.ptr()) {
       allocator_.free(const_cast<char *>(str.ptr()));
     }
+    str.reset();
   }
-  sys_path_buffer_.reset();
   cur_level_ = 1;
-  sys_path_buffer_.reset();
   // TODO:shanting 计划生成时记录右表是否有含参数的条件下推，如果没有可以不做datum_store_的rebuild
   if (true) {
     datum_store_.reset();

src/sql/engine/connect_by/ob_nl_cnnt_by_op.cpp

@@ -310,6 +310,7 @@ int ObNLConnectByOp::inner_close()
   if (nullptr != mem_context_) {
     mem_context_->reuse();
   }
+  connect_by_pump_.sys_path_buffer_.reset();
   return ret;
 }