MDEV-27365 CREATE-or-REPLACE SEQUENCE is binlogged without DDL flag

CREATE-OR-REPLACE SEQUENCE is not logged with Gtid event DDL flag
which affects its slave parallel execution.
Unlike other DDL:s it can occur in concurrent execution with following transactions
which can lead to various errors, including asserts like

(mdl_request->type != MDL_INTENTION_EXCLUSIVE && mdl_request->type != MDL_EXCLUSIVE) || !(get_thd()->rgi_slave && get_thd()->rgi_slave->is_parallel_exec && lock->check_if_conflicting_replication_locks(this)

in MDL_context::acquire_lock.

Fixed to wrap internal statement level commit with save-
and-restore of TRANS_THD::m_unsafe_rollback_flags.

mysql-test/suite/binlog/t/binlog_parallel_replication_ddl.test

@@ -0,0 +1,30 @@
+# Check binlog properties of various DDL:s.
+# Motivated by MDEV-27365.
+#
+--source include/have_log_bin.inc
+--source include/have_binlog_format_mixed.inc
+
+RESET MASTER;
+
+# MDEV-27365 CREATE-or-REPLACE SEQUENCE bilogged without DDL flag
+# Prove it is logged with the DDL flag.
+CREATE OR REPLACE SEQUENCE s1;
+
+# This one has been always correct.
+DROP SEQUENCE s1;
+FLUSH LOGS;
+
+--let $MYSQLD_DATADIR= `select @@datadir`
+--exec $MYSQL_BINLOG --base64-output=decode-rows $MYSQLD_DATADIR/master-bin.000001 > $MYSQLTEST_VARDIR/tmp/mysqlbinlog.sql
+
+--let SEARCH_PATTERN= GTID [0-9]+-[0-9]+-[0-9]+
+--let SEARCH_FILE= $MYSQLTEST_VARDIR/tmp/mysqlbinlog.sql
+--source include/search_pattern_in_file.inc
+
+--echo The same as above number of samples must be found:
+--let SEARCH_PATTERN= GTID [0-9]+-[0-9]+-[0-9]+ ddl
+--let SEARCH_FILE= $MYSQLTEST_VARDIR/tmp/mysqlbinlog.sql
+--source include/search_pattern_in_file.inc
+--remove_file $MYSQLTEST_VARDIR/tmp/mysqlbinlog.sql
+
+--echo End of the tests