Refs: MW-245 - changed logic so that in non primary node it is possible to do SET + SHOW + SELECT from information and pfs schema, when dirty reads are not enabled - however, non table selects are not allowed (e.g. SELECT 1)

Refs MW-245 - logic was wrong in detecting if queries are allowed in non primary node. it allowed select with no table list to execute even if dirty reads was not specified

refs MW-245 - allowing USE <database> with dirty reads configuration - fix for logic of setting wsrep ready status

MDEV-12737: tokudb_mariadb.mdev6657 fails in buildbot with different plan, and outside with valgrind warnings

Fixing the test by adding replace column for the rows column in the explain.

MDEV-10991: Server crashes in spider_udf_direct_sql_create_conn - tests in spider/oracle* suites crash the server

The crash occurs due to code that is #ifdef'd out with HAVE_ORACLE_OCI that
pertains to the use of Spider with an Oracle data tier. Enabling this code
eliminates the crash.

The reason that MariaDB needs to support Oracle storage at the data tier is
to help customers migrate from Oracle. It is necessary to build Spider with
the additional build flag -DHAVE_ORACLE_OCI, and install and start Oracle
before running the Oracle test suite or any tests within it. Nevertheless,
if Spider is built normally and Oracle has not been started, these tests
should not cause the MariaDB server to crash. The bug fix replaces the
crash with the following error:
  ERROR 12501 (HY000) at line 4: The connect info 'ORACLE' is invalid

Author:
  Jacob Mathew.

Reviewer:
  Kentoku Shiba.

cmp_item_sort_string::store_value() did not cache the string returned
from item->val_str(), whose result can point to various private members
such as Item_char_typecast::tmp_value.

- cmp_item_sort_string::store_value() remembered the pointer returned
  from item->val_str() poiting to tmp_value into cmp_item_string::value_res.
- Later, cmp_item_real::store_value() was called, which called
  Item_str_func::val_real(), which called Item_char_typecast::val_str(&tmp)
  using a local stack variable "String tmp". Item_char_typecast::tmp_value
  was overwritten and become a link to "tmp":
  tmp_value.Ptr freed its own buffer and set to point to the buffer
  owned by "tmp".
- On return from Item_str_func::val_real(), "String tmp" was destructed,
  but "tmp_value" still pointed to the buffer owned by "tmp",
  So tmp_value.Ptr became invalid.
- Then cmp_item_sort_string() passed cmp_item_string::value_res to sortcmp().
  At this point, value_res still pointed to an invalid value of
  Item_char_typecast::tmp_value.

Fix:
changing cmp_item_sort_string::store_value() to force copying
to cmp_item_string::value if item->val_str(&value) returned
a different pointer (instead of &value).

Fix test failure on galera_flush_local.

Fix test failure on galera_concurrent_ctas

    Fortify wsrep_hton so that wsrep calls are not done to NULL-pointers.

To disallow equality propagation for DATETIME with non-zero YYYYMMDD part we were setting null_value to true.
This caused issues when we were calculating selectivity for a condition as this returned IMPOSSIBLE WHERE.

The issue is resolved by not setting null_value to true for DATETIME with non-zero YYYYMMDD.

Eliminated last exit() call from libmysqld.

Unlike commit a54abf01 claimed,
the caller of THD::awake() may actually hold the InnoDB lock_sys->mutex.
That commit introduced a deadlock of threads in the replication slave
when running the test rpl.rpl_parallel_optimistic_nobinlog.

lock_trx_handle_wait(): Expect the callers to acquire and release
lock_sys->mutex and trx->mutex.

innobase_kill_query(): Restore the logic for conditionally acquiring
and releasing the mutexes. THD::awake() can be called from inside
InnoDB while holding one or both mutexes, via thd_report_wait_for() and
via wsrep_innobase_kill_one_trx().

ha_innobase::unlock_row(): Use a relaxed version of the
trx_state_eq() debug assertion, because rr_unlock_row()
may be invoked after an error has been already reported
and the transaction has been rolled back.

By definition, c_lock->trx->lock.wait_lock==c_lock cannot hold.
That is, the owner transaction of a lock cannot be waiting for that
particular lock. It must have been waiting for some other lock.
Remove the dead code related to that. Also, test c_lock for NULLness
only once.

The caller of THD::awake() should never hold any InnoDB mutexes,
so we can always acquire lock_sys->mutex and trx->mutex.

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

Two changes were made to the test:

1) Suppress warning "Refusing exit for the last slave thread."
   This warning was already suppressed, but on the wrong node.

2) The test occasionally fails because it expects that the
   number of applier threads changes immediately after
   changing the value of ```variable wsrep_slave_threads```.
   Which is not true. This patch turns snippets like this:

   ```
   SET GLOBAL wsrep_slave_threads = x;
   SELECT COUNT(*) = x FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user';
   ```

   Into proper wait_conditions:

   ```
   SET GLOBAL wsrep_slave_threads = x;
   let $wait_condition = SELECT COUNT(*) = x FROM ...;
   --source include/wait_condition.inc
   ```

MDEV-14144 Fix for MTR tests complaining "Query didn't return a result set"

MDEV-13549 Fix for test galera.galera_var_max_ws_rows

MDEV-13549 Fix and re-enable MTR test galera.MW-366

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

MDEV-13549 Fix and re-enable test galera.MW-286

These tests were also subject to error "Wrong usage of mutex
'LOCK_wsrep_thd' and 'LOCK_thd_kill'".

As this is the only moderately critical fopened for writing file,
create an alternate path to use open and fdopen for non-glibc platforms
that support O_CLOEXEC (BSDs).

Tested on Linux (by modifing the GLIBC defination) to take this
alternate path:

$ cd /proc/23874
$ more fdinfo/71
pos:    0
flags:  02100001
mnt_id: 24
$ ls -la fd/71
l-wx------. 1 dan dan 64 Mar 14 13:30 fd/71 -> /dev/shm/var_auto_i7rl/mysqld.1/data/ib_buffer_pool.incomplete

"mtr func_date_add" failed on 32-bit platforms. Removing a wrong case to "long".
Both values[] and log_10_int[] are arrays of "ulonglong", no cast is needed.

musl ships the header for other purposes, but makecontext is not
implemented. fix the check to detect if makecontext is implemented
before enabling code using it.

Test passes reliably after applying missing commit from upstream.

The test was not deterministic as it would not wait for the second
INSERT to be applied (and thus the victim transaction rolled back).

MDEV-8743: ib_logfile0 Use O_CLOEXEC so galera SST scripts don't get fd

Test galera.MW-366 is not deterministic and depends on timing assumptions.
The test occasionally fails after checking the number of 'system user'
processes in processlist after changing the value of variable global
wsrep_slave_threads, like this:
```
SET GLOBAL wsrep_slave_threads = x;
--sleep 0.5
SELECT COUNT(*) = x FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user';
```

The problem is that the number of slave threads is internally adjusted
'asynchronously', and it may take some time to spawn/kill new threads,
especially in a heavily loaded system.

This patch removes the '--sleep 0.5' statements from the test and replaces
those with appropriate wait conditions, like this:
```
SET GLOBAL wsrep_slave_threads = x;
let $wait_condition = SLECT COUNT(*) = x FROM ...;
--source include/wait_condition.inc
```