Disable a failing test

Author: dr-m

mysql-test/suite/galera/disabled.def

@@ -50,4 +50,5 @@ MW-328C : MDEV-17847 Galera test failure on MW-328[A|B|C]
 galera.galera_encrypt_tmp_files : Get error failed to enable encryption of temporary files
 galera.galera_var_reject_queries : assertion in inline_mysql_socket_send
 query_cache : MDEV-18137: Galera test failure on query_cache
+galera.galera_autoinc_sst_mariabackup : MDEV-18177 Galera test failure on galera_autoinc_sst_mariabackup
 galera_gcache_recover_manytrx : MDEV-15740