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

Add check that file key management plugin is found.

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

@@ -96,6 +96,8 @@ 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_xtrabackup.inc'} = 'Need innobackupex'
              unless which(innobackupex);
   $skip{'include/have_xtrabackup.inc'} = 'Need socat or nc'

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/have_mariabackup.inc