trx_rseg_t::is_persistent(): Correct a bogus debug assertion.

log_group_read_log_seg(): Always return false when returning
before reading end_lsn.

xtrabackup_copy_logfile(): On error, indicate whether
a corrupt log record was encountered.

Only xtrabackup_copy_logfile() in Mariabackup cared about the
return value of the function. InnoDB crash recovery was not
affected by this bug.

By pure chance the macro worked in the cases it was used, but
better to get this fixed!

dict_create_foreign_constraints_low(): Clean up the way in
which the error messages are initialized, and ensure that
the table name is always initialized.

Fix incremental prepare to copy #rocksdb subdirectory from the
incremental dir.

If --debug=d,innodb_skip_monitors is specified, skip the creation
of srv_error_monitor_thread and srv_monitor_thread. In this way,
interactive debugging sessions will not be interfered by messages
about a mutex or rw_lock being held for a long time.

Closes #1192

In tests that directly write InnoDB data file pages,
compute the innodb_checksum_algorithm=crc32 checksums,
instead of writing the 0xdeadbeef value used by
innodb_checksum_algorithm=none. In this way, these tests
will not cause failures when executing
./mtr --mysqld=--loose-innodb-checksum-algorithm=strict_crc32

The variable is obsolete.
In mariabackup --backup, encryption plugin loading code sets the value
this parameter to the same as in server.

In mariabackup --prepare, no new redo  log is generated,
and xtrabackup_logfile is removed after it anyway.

Remove 'register' quantifer from args too.

This was added in 29fa7252 (in 2000) and nothing defines
NEW_HASH_FUNCTION. A low collision is the wrong tradeoff,
it should be focused on throughput.

d405bee0 shows the existing function
is pretty cpu intensive and needs to be improved as well.

- CREATE TABLE ... SELECT drops constraints for columns that
  are both in the create and select part.
  - Fixed by copying the constraint in
    Column_definiton::redefine_stage1_common()
- If one has both a default expression and check constraint for a
  column, one can get the error "Expression for field `a` is refering
  to uninitialized field `a`.
  - Fixed by ignoring default expressions for current column when checking
    for CHECK constraint

According to close(2) "Retrying the close() after a failure return is
the wrong thing to do"

Even the EINTR case its maybe closed. Take the prudent approach here
an risk leaking one file descriptor rather than closing one that is
nolonger ours.

No need to call list.empty(): first one is called by List constructor,
second one doesn't make sense as the object is destroyed immediately
afterwards.

Also always empty list rather than only if there is no error.

cmake/submodules: notify user about gitconfig for automatic update

Co-Authored-By: grooverdan <daniel@linux.ibm.com>

Most of the mtr tests in the galera_3nodes suite fail
for a variety of reasons with a variety of errors.

This patch fixes several substantial flaws
in the galera_3nodes suite tests and in the mtr framework
service files, adapting the tests from galera_3nodes
for the current version of MariaDB.

This patch also synchronizes some galera_3nodes-related
files with the latest changes made for MDEV-17835 (v2 patch)
and for MDEV-18379 in other branches (10.2 and 10.3).

Closes #1161

When importing a tablespace, we must initialize dummy DEFAULT NULL
values for any instantly added columns in order to avoid a debug
assertion failure when PageConverter::update_records() invokes
rec_get_offsets(). Finally, when the operation completes, we must
evict and reload the table definition, so that the correct
default values for instantly added columns will be loaded.

ha_innobase::discard_or_import_tablespace(): On successful
IMPORT TABLESPACE, evict and reload the table definition,
so that btr_cur_instant_init() will load the correct metadata.

PageConverter::update_index_page(): Fill in dummy DEFAULT NULL values
for instantly added columns. These will be replaced upon the
completion of the operation by evicting and reloading the metadata.

row_discard_tablespace(): Invoke dict_table_t::remove_instant().
After DISCARD TABLESPACE, the table is no longer in "instant ALTER"
format, because there is no data file attached.

The code path where the table was not being rebuilt during ALTER TABLE
was not covered by the test. Add coverage, and remove the debug assertion
that could fail in this case.

Followup for db8f0dae

and in fef9013d

fixes memory leaks in restart_mysqld.inc tests

Followup for 8f5ea83f

MDEV-18426: Most of the mtr tests in the galera_3nodes suite fail

- Fixes building with galera and tokudb
- Added support for --without-wsrep BUILD script option

- Backport from 10.4