The following changes are committed:

* `RESET MASTER` at the end of the test. This was necessary to allow the test
  to run on repeated runs.

* `--source include/galera_wait_ready.inc` after setting `gmcast.isolate=0` to
  get back to a primary component.

* Fix for assertion in `Protocol::end_statement()`. The assertion is due to
  the fact that function `do_command()` calls `thd->protocol->end_statement()`,
  without setting an error, when it is detected that galera is not ready yet.
  Following line somehow disappeared in a past merge:
  ```
  my_message(ER_UNKNOWN_COM_ERROR,
             "WSREP has not yet prepared node for application use", MYF(0));
  ```

Fix test failure on galera_toi_dll_fk_insert. DEFAULT value seems
to be 3 but test expects it to be 1.

MDEV-13549 Fix and re-enable MTR test galera.mysql-wsrep#90

MDEV-13549 Fix and re-enable MTR test galera.galera_gra_log

Test galera checks that a `GRA_x_x.log` file is created whenever
wsrep applier fails to apply some replication event. The file
contains the corresponding binlog event that failed to apply.
The test creates a new file by concatenating a pre-recorded
file containing the binlog header (see `std-data/binlog-header.log`)
and the `GRA_x_x.log` file. The test then checks that the resulting
file, containing the binlog header and the event that failed to
apply, is correctly read by `mysqlbinlog` program.
The test fails in MariaDB because the GRA_x_x.log file created
by MariaDB already contains the binlog header (see MDEV-7867).
This patch fixes/simplifies test `galera.galera_gra_log` so that
it doesn't concatenate `std-data/binlog-header.log` with the
`GRA_x_x.log` file. File `std-data/binlog-header.log` is deleted
altoghether, because not used by any other test.

(Currently) LibreSSL doesn't calculate the string length of the hostname
that's passed to X509_check_host automatically in case namelen/chklen is 0.
This causes server certificate validation to fail when building MariaDB with
LibreSSL.

The proposed fix makes MariaDB determine the string length passed to
X509_check_host. As there are no ill side-effects (OpenSSL's X509_check_host
also simply calls strlen if namelen == 0, see also X509_check_host(3)), this
wasn't wrapped in any #ifdef like constructs.

Please see here for a proposed patch to modify LibreSSL's behavior:
https://github.com/libressl-portable/openbsd/pull/87

MariaDB adjustments.

mysqltest.cc : Allow 12 error codes at --error

wait_until_connected_again.inc: Replace numeric error codes with symbols

mysqltest.test: Add error codes to test that tests too many errorcodes

kill_galera.inc can no longer rely on wait_until_connected_again.inc.
This is because wait_until_connected_again now tries to make sure
that the server it is connected eventually transition to ready
state. Whereas some tests may need to kill galera while the server
is in a non-primary view.

Test galera_3nodes.galera_pc_weight started to fail because it
expects to use wait_until_connected_again while remaining in
non-primary view. Hopefully this is the only test which makes
this assumption, and fortunately those wait_until_connected_again
seem unnecessary, so this patch removes them.

Remove clause on `thd->variables.wsrep_on` in the following code:

if (WSREP(thd))
{
...
        if (thd->variables.wsrep_on &&
            ...

In the above snippet, `WSREP(thd)` already ensures thd->variables.wsrep_on

wait_until_connected_again issues 'SHOW STATUS' query repeatedly
until mysqld replies without errors.
However, SHOW STATUS is treated specially by wsrep in that it is
allowed to proceed even if wsrep is not yet in ready state. As a
consequence, after returning from wait_until_connected_again,
wsrep may not be ready yet and subsequent queries may fail with
error "1047 WSREP has not yet prepared node for application use".
To avoid those errors, the patch includes wait_wsrep_ready.inc at
the end of the wait_until_connected_again.

Test was missing DEBUG_SYNC cleanup `SET DEBUG_SYNC ='RESET'`.

MDEV-13549 Fix and re-enable MTR test galera.galera_gtid_slave

MDEV-13549 Fix and re-enable MTR test galera.galera_as_master

This patch makes two changes:

* It replaces `--sleep 1` with appropriate wait_conditions, and
  removes another `--sleep 1` which is no longer necessary, after
  MDEV-14144 has been fixed.

* It moves the `RESET MASTER` from node_1 at the very end, when it
  it sure that the other nodes have applied the the final cleanup
  `DROP TABLE t1,t2.`
  This solves the problem with the `DROP TABLE` not being replicated
  to the asynchronous slaves, which would make the test fail with:
  `Timeout in wait_condition.inc for SELECT COUNT(*) = 0 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 't1';`

MDEV-13549 Fix and re-enable test galera.galera_suspend_slave

Was failing due to missing RESET MASTER

Test galera_suspend_slave checks that after suspending a galera
node, like this:
```
--perl
        my $pid_filename = $ENV{'NODE_2_PIDFILE'};
        my $mysqld_pid = `cat $pid_filename`;
        chomp($mysqld_pid);
        system("kill -SIGSTOP $mysqld_pid");
        exit(0);
EOF
```

the remaining one node cluster is no longer able to successfully
INSERT new rows:
```
--error ER_UNKNOWN_COM_ERROR,ER_LOCK_WAIT_TIMEOUT,ER_LOCK_DEADLOCK,ER_ERROR_DURING_COMMIT
INSERT INTO t1 VALUES (1);
```

On rare occasions when the system is overloaded, it appears that
suspending the process with ```system("kill -SIGSTOP $mysqld_pid")```
takes some time, enough for the subsequent INSERT to succeed. In which
case the test fails because it rightly expects the INSERT to fail.

To fix the problem, the patch makes sure that the cluster has shrinked
to one node, before trying to INSERT the new value.

MDEV--15609 engines/funcs.crash_manytables_number crashes with error 24
           (too many open files)
MDEV-10286  Adjustment of table_open_cache according to system limits
            does not work when open-files-limit option is provided

Fixed by adjusting tc_size downwards if there is not enough file
descriptors to use.

Other changes:
- Ensure that there is 30 (was 10) extra file descriptors for other usage
- Decrease TABLE_OPEN_CACHE_MIN to 200 as it's better to have a smaller
  table cache than getting error 24
- Increase minimum of max_connections and table_open_cache from 1 to 10
  as 1 is not usable for any real application, only for testing.

and remove redundant have_innodb.inc, it's included in
galera_cluster.inc anyway.

and remove redundant have_innodb.inc, it's included in
galera_cluster.inc anyway.

extra/mariabackup/ds_buffer.c:145:9: warning: pointer targets in assignment differ in signedness [-Wpointer-sign]

information can be obtained.

plugin only enabled for Linux, as it fails building on BSD/MacOSX.
disks.test fixed.

information can be obtained.

disks.test moved to plugin's directory.

Changed "local" datasink logic to detect page compressed Innodb tables.

Whenever such table is detected, holes in the copied files are created by
skipping over binary zeros at the end of each compressed page.

             time and don't let server shut down

Queries from I_S in "Filling schema table" state didn't check killed
flag. For large tables this phase may take a while to complete.

Fixed by adding thd->killed flag check for each processed row.

galera SST tests have a debug part, but we don't want to limit them
to fulltest2 builder. So, add support for test files that
have a debug part:

* add maybe_debug.inc and maybe_debug.combinations
* 'debug' combination is run when debug is available
* 'release' combination is run otherwise
* test wraps debug parts in if($with_debug) { ... }
* and creates ,debug.rdiff for debug results

create galera.galera_sst_mariabackup

* make galera.galera_sst_xtrabackup* not big
* auto-select between socat and nc, whatever available
* auto-skip xtrabackup tests if no xtrabackup or neither socat nor nc

make galera.galera_sst_rsync not big

fix galera.galera_sst_mysqldump test to work:
* must connect to 127.0.0.1, where mysqld is listening
* disable wsrep_sync_wait in wsrep_sst_mysqldump, otherwise
  sst can deadlock
* allow 127.0.0.1 for bind_address and wsrep_sst_receive_address.
  (it's useful in tests, or when two nodes are on the same box,
  or when nodes are on different boxes, but the connection is
  tunelled, or whatever. Don't judge user's setup). MDEV-14070
* don't wait for client connections to die when doing
  mysqldump sst. they'll die in a due time, and if needed mysql
  will wait on locks until they do. MDEV-14069

Also don't mark it big, to make sure it's sufficiently tested

wsrep_sst_auth_init() is always invoked with value==wsrep_sst_auth.
Old code was leaking value, because it was never freed.