MDEV-28301 Spider: Fix GCC warnings, comparing the result of pointer addition ... and NULL

The condition of the if statements are always true.

storage/spider/spd_db_mysql.cc

@@ -3444,27 +3444,15 @@ int spider_db_mbase::append_lock_tables(
     conn_link_idx = tmp_spider->conn_link_idx[tmp_link_idx];
     spider_mbase_share *db_share = (spider_mbase_share *)
       tmp_spider->share->dbton_share[conn->dbton_id];
-    if (&db_share->db_names_str[conn_link_idx])
-    {
-      db_name = db_share->db_names_str[conn_link_idx].ptr();
-      db_name_length = db_share->db_names_str[conn_link_idx].length();
-      db_name_charset = tmp_spider->share->access_charset;
-    } else {
-      db_name = tmp_spider->share->tgt_dbs[conn_link_idx];
-      db_name_length = tmp_spider->share->tgt_dbs_lengths[conn_link_idx];
-      db_name_charset = system_charset_info;
-    }
-    if (&db_share->table_names_str[conn_link_idx])
-    {
-      table_name = db_share->table_names_str[conn_link_idx].ptr();
-      table_name_length = db_share->table_names_str[conn_link_idx].length();
-      table_name_charset = tmp_spider->share->access_charset;
-    } else {
-      table_name = tmp_spider->share->tgt_table_names[conn_link_idx];
-      table_name_length =
-        tmp_spider->share->tgt_table_names_lengths[conn_link_idx];
-      table_name_charset = system_charset_info;
-    }
+
+    db_name = db_share->db_names_str[conn_link_idx].ptr();
+    db_name_length = db_share->db_names_str[conn_link_idx].length();
+    db_name_charset = tmp_spider->share->access_charset;
+
+    table_name = db_share->table_names_str[conn_link_idx].ptr();
+    table_name_length = db_share->table_names_str[conn_link_idx].length();
+    table_name_charset = tmp_spider->share->access_charset;
+
     if ((error_num = spider_db_mbase_utility->
       append_lock_table_body(
         str,