MDEV-17771: Add Galera ist and sst tests using mariabackup

Add check that file key management plugin is found.

mysql-test/suite/galera/disabled.def

@@ -56,4 +56,3 @@ galera_sst_xtrabackup-v2-options : xtrabackup is deprecated
 galera_ist_innodb_flush_logs : xtrabackup is deprecated
 galera_sst_xtrabackup-v2 : xtrabackup is deprecated
 
-galera_sst_mariabackup_table_options : refuses to start due to encryption

mysql-test/suite/galera/include/have_filekeymanagement.inc

+#
+# Used in galera/suite.pm to check file key management plugin
+#

mysql-test/suite/galera/suite.pm

@@ -98,6 +98,8 @@ if (which(socat)) {
 
 sub skip_combinations {
   my %skip = ();
+  $skip{'include/have_filekeymanagement.inc'} = 'needs file_key_management plugin'
+             unless $ENV{FILE_KEY_MANAGEMENT_SO};
   $skip{'include/have_mariabackup.inc'} = 'Need mariabackup'
              unless which(mariabackup);
   $skip{'include/have_mariabackup.inc'} = 'Need ss'

mysql-test/suite/galera/t/galera_sst_mariabackup_table_options.test

 --source include/big_test.inc
 --source include/galera_cluster.inc
+--source include/have_filekeymanagement.inc
 --source include/innodb_encrypt_tables.inc
 --source include/innodb_page_size_small.inc
 --source include/have_mariabackup.inc