MDEV-9038 Binlog encryption tests

- created binlog_encryption test suite and added it to the default list
- moved some tests from rpl, binlog and multisource suites to extra
  so that they could be re-used in different suites
- made minor changes in include files

mysql-test/suite/binlog_encryption/restart_server.inc

@@ -0,0 +1,35 @@
+#
+# We can not use the common include/restart_mysqld.inc or include/rpl_restart_server.inc,
+# because they have hardcoded connection names (master, master1) 
+# which are not initiated by rpl_init.inc.
+# This is the relevant and simplified part of the same set of scripts.
+#
+# ==== Usage ====
+#
+# --let $rpl_server_number= N
+#     Number to identify the server that needs to reconnect.
+#     1 is the master server, 2 the slave server
+# [--let $rpl_server_parameters= --flag1 --flag2 ...]
+# --source restart_server.inc
+#
+
+--let $_cur_con= $CURRENT_CONNECTION
+
+--connection default
+--enable_reconnect
+
+--connection $_cur_con
+--enable_reconnect
+--exec echo "wait" > $MYSQLTEST_VARDIR/tmp/mysqld.$rpl_server_number.expect
+
+shutdown_server 10;
+
+--source include/wait_until_disconnected.inc
+
+--let $_rpl_start_server_command= restart
+if ($rpl_server_parameters)
+{
+  --let $_rpl_start_server_command= restart:$rpl_server_parameters
+}
+--exec echo "$_rpl_start_server_command" > $MYSQLTEST_VARDIR/tmp/mysqld.$rpl_server_number.expect
+--source include/wait_until_connected_again.inc