Part2: MDEV-18156 Assertion `0' failed or `btr_validate_index(index, 0, false)' in row_upd_sec_index_entry or error code 126: Index is corrupted upon DELETE with PAD_CHAR_TO_FULL_LENGTH

This patch allows the server to open old tables that have
"bad" generated columns (i.e. indexed virtual generated columns,
persistent generated columns) that depend on sql_mode,
for general things like SELECT, INSERT, DROP, etc.
Warning are issued in such cases.

Only these commands are now disallowed and return an error:
- CREATE TABLE introducing a "bad" generated column
- ALTER TABLE introducing a "bad" generated column
- CREATE INDEX introdicing a "bad" generated column
  (i.e. adding an index on a virtual generated column
   that depends on sql_mode).

Note, these commands are allowed:
- ALTER TABLE removing a "bad" generate column
- ALTER TABLE removing an index from a "bad" virtual generated column
- DROP INDEX removing an index from a "bad" virtual generated column
but only if the table does not have any "bad" columns as a result.

MDEV-18156 Assertion `0' failed or `btr_validate_index(index, 0, false)' in row_upd_sec_index_entry or error code 126: Index is corrupted upon DELETE with PAD_CHAR_TO_FULL_LENGTH

This change takes into account a column's GENERATED ALWAYS AS
expression dependcy on sql_mode's PAD_CHAR_TO_FULL_LENGTH and
NO_UNSIGNED_SUBTRACTION flags.

Indexed virtual columns as well as persistent generated columns are
now not allowed to have such dependencies to avoid inconsistent data
or index files on sql_mode changes.
So an error is now returned in cases like this:

  CREATE OR REPLACE TABLE t1
  (
    a CHAR(5),
    v VARCHAR(5) AS (a) PERSISTENT -- CHAR->VARCHAR or CHAR->TEXT = ERROR
  );

Functions RPAD() and RTRIM() can now remove dependency on
PAD_CHAR_TO_FULL_LENGTH. So this can be used instead:

  CREATE OR REPLACE TABLE t1
  (
    a CHAR(5),
    v VARCHAR(5) AS (RTRIM(a)) PERSISTENT
  );

Note, unlike CHAR->VARCHAR and CHAR->TEXT this still works,
not RPAD(a) is needed:

  CREATE OR REPLACE TABLE t1
  (
    a CHAR(5),
    v CHAR(5) AS (a) PERSISTENT -- CHAR->CHAR is OK
  );

More sql_mode flags may affect values of generated columns.
They will be addressed separately.

See comments in sql_mode.h for implementation details.

This allows one to run the test suite even if any of the following
options are changed:
- character-set-server
- collation-server
- join-cache-level
- log-basename
- max-allowed-packet
- optimizer-switch
- query-cache-size and query-cache-type
- skip-name-resolve
- table-definition-cache
- table-open-cache
- Some innodb options
etc

Changes:
- Don't print out the value of system variables as one can't depend on
  them to being constants.
- Don't set global variables to 'default' as the default may not
  be the same as the test was started with if there was an additional
  option file. Instead save original value and reset it at end of test.
- Test that depends on the latin1 character set should include
  default_charset.inc or set the character set to latin1
- Test that depends on the original optimizer switch, should include
  default_optimizer_switch.inc
- Test that depends on the value of a specific system variable should
  set it in the test (like optimizer_use_condition_selectivity)
- Split subselect3.test into subselect3.test and subselect3.inc to
  make it easier to set and reset system variables.
- Added .opt files for test that required specfic options that could
  be changed by external configuration files.
- Fixed result files in rockdsb & tokudb that had not been updated for
  a while.

This was done to be able to get any information why the embedded server
doesn't start.

These was part of an incomplete old merge from MySQL 5.6

Caused by:
MDEV-18501 Partition pruning doesn't work for historical queries (cleanup)

gcc 7.4.1

Pruning fix for SYSTEM_TIME INTERVAL partitioning.

Allocating one more element in range_int_array for CURRENT partition
is required for RANGE pruning to work correctly
(get_partition_id_range_for_endpoint()).

SYSTEM_TYPE partitioning: COLUMN properties removed. Partitioning is
now pure RANGE based on UNIX_TIMESTAMP(row_end).

DECIMAL type is now allowed as RANGE partitioning, we can partition by
UNIX_TIMESTAMP() (but not for DATETIME which depends on local timezone
of course).

Cleanup removes useless allocation.

FIXME: rocksdb.drop_table hangs on shutdown, but is not disabled in 10.2

row_upd_build_difference_binary(): Correctly handle the
case where columns (or clustered index fields) have been added
since the 'entry' was originally created. In this case,
the update vector must replace any missing columns with the
default values of the instantly added columns.

Merge the changes to include/index_merge*inc from the upstream. The changes
add this command in many places:

 +if ($engine_type == RocksDB)
 +{
 +    set global rocksdb_force_flush_memtable_now=1;
 +}

also add it in one more place to make the test truly stable.

With --skip-debug-assert, DBUG_ASSERT(false) will allow execution to
continue. Hence, we will need /* fall through */ after them.

Some DBUG_ASSERT(0) were replaced by break; when the switch () statement
was followed by DBUG_ASSERT(0).

Adjust the testcase according to the review input

(Backported to 10.3, addressed review input)

Sj_materialization_picker::check_qep(): fix error in cost/fanout
calculations:
- for each join prefix, add #prefix_rows / TIME_FOR_COMPARE to the cost,
  like best_extension_by_limited_search does
- Remove the fanout produced by the subquery tables.
- Also take into account join condition selectivity

optimize_wo_join_buffering() (used by LooseScan and FirstMatch)
- also add #prefix_rows / TIME_FOR_COMPARE to the cost of each prefix.
- Also take into account join condition selectivity

The test occasionally fails with different table reference count
due to purge activity after INSERT operations (MDEV-12288).
Wait for purge before accessing dict_table_t::n_ref_count.

Merge a part of commit 25af2a18.
This was forgotten in the
merge commit e41eb044.

Commit 536215e3 in MariaDB Server 10.3.1
introduced the compiler flag (not cmake option) DBUG_ASSERT_AS_PRINTF
that converts DBUG_ASSERT in non-debug builds into printouts.

For debug builds, it could be useful to be able to convert DBUG_ASSERT
into a warning or error printout, to allow execution to continue.
This would allow debug builds to be used for reproducing hard failures
that occur with release builds.

my_assert: A Boolean flag (set by default), tied to the new option
debug_assert that is available on debug builds only.
When set, DBUG_ASSERT() will invoke assert(), like it did until now.
When unset, DBUG_ASSERT() will invoke fprintf(stderr, ...)
with the file name, line number and assertion expression.

Changes of PAGE_MAX_TRX_ID must be redo-logged for correctness.
That was fixed in the InnoDB Plugin for MySQL 5.1 already.

Improved handling of subdirectories in the xtrabackup-v2 SST scripts (similar to MDEV-18863) for more predictable test results (related to xtrabackup-v2 SST)

MDEV-16932: ASAN heap-use-after-free in my_charlen_utf8 / my_well_formed_char_length_utf8 on 2nd execution of SP with ALTER trying to add bad CHECK

Make automatic name generation during execution (not prepare).

Check result of memory allocation operation.

Some bugs are detected only after a table definition has been evicted
and then reloaded to the InnoDB data dictionary cache.

For debug builds, introduce the settable Boolean configuration parameter
innodb_evict_tables_on_commit_debug that can be set to request InnoDB
to attempt to evict table definitions from the data dictionary cache
whenever a transaction is committed.

This has been tested on 10.3 and 10.4 with the following:

./mysql-test-run.pl --mysqld=--loose-innodb-evict-tables-on-commit-debug

You can also use the following:

SET GLOBAL innodb_evict_tables_on_commit_debug=ON;
SET GLOBAL innodb_evict_tables_on_commit_debug=OFF;

The parameter affects the commit (or rollback or abort) of
transactions that have modified persistent InnoDB tables.

Revert part of fa2a74e0.

trx_reference(): Remove, and merge the relevant part to the only caller
trx_rw_is_active(). If the statements trx = NULL; were ever executed,
the function would have dereferenced a NULL pointer and crashed in
trx_mutex_exit(trx). Hence, those statements must have been unreachable,
and they can be replaced with debug assertions.

trx_rw_is_active(): Avoid unnecessary acquisition and release of trx->mutex
when do_ref_count=false.

lock_trx_release_locks(): Do not reset trx->id=0. Had the statement been
necessary, we would have experienced crashes in trx_reference().