Up to MariaDB 10.2, field_name is still a C-style string.

- Changed the assert to ignore SRV_LOG_SPACE_FIRST_ID. Post push
fix to address the previous commit failure.

Changed the debug insert inside fil_io() to check whether it writes
the page to wrong offset only for user tablespace.

- log_crypt_init() should be called from create_log_files(). Because
it should re-create the new random nonce compared to the old ones.

The test innodb.leaf_page_corrupted_during_recovery
fails on buildbot with

Warning	1406	Data too long for column 'line' at row 10
line
 len 16384; hex ...

because of a page dumps that InnoDB is generating for a corrupted page

Since this test is using debug instrumentation, we will solve the
issue by disabling page dumps in debug builds altogether. Users of
debug builds will likely know how to extract page dumps in other means.

Page dump output could sometimes be useful when diagnosing problems
that users are facing. Hence we will keep the page dump output in
non-debug (release) builds.

MDEV-19914 Server startup fails while dropping garbage encrypted tablespace if innodb_encryption_threads > 0

- Avoiding accessing encryption thread mutex before initiating
the encryption threads

- Ported mysql Bug#20597981 test case to mariadb-10.2
- InnoDB never used fts_doc_id_in_read_set. Basically it tells
innodb to read the fts_doc_id from the index record itself.

- Introduce a new variable called innodb_encrypt_temporary_tables which is
a boolean variable. It decides whether to encrypt the temporary tablespace.
- Encrypts the temporary tablespace based on full checksum format.
- Introduced a new counter to track encrypted and decrypted temporary
tablespace pages.
- Warnings issued if temporary table creation has conflict value with
innodb_encrypt_temporary_tables
- Added a new test case which reads and writes the pages from/to temporary
tablespace.

Added the condition in innochecksum tool to check page id mismatch.
This could catch the write corruption caused by InnoDB.

Added the debug insert inside fil_io() to check whether it writes
the page to wrong offset.

A fix in MySQL 5.7.6 was not completely merged to MariaDB:
Bug#19419026 WHEN A TABLESPACE IS NOT FOUND, DO NOT REPORT "TABLE NOT FOUND"

Decrease array on stack in open_or_create_log_file() to avoid stack overflow.

The problem was that the code in maria_extra assumed that there could be
only one table open when doing maria_extra(MA_FORCE_REOPEN)
However in the case of triggers, there can be multiple copies of
the table open.

Fixed by removing assert.

This was accidentally broken in the parent commit.

Also, move part of the test back to innodb.innodb_mysql
and another part to a new test innodb.purge.

Last but not least, merge the tests innodb_zip.4k and innodb_zip.8k
to innodb_zip.page_size.

MariaDB doesn't support Read-Free replication, so showing them only causes
confusion.
Removed variables:
- @@rocksdb_read_free_rpl
- @@rocksdb_read_free_rpl_tables

Check FILE privelege.

Colors possibility auto detected. [ such ] stuff is colored.

Patch by Sergei Golubchik

The test cases for the MDEV found several independent bugs
in MariaDB server and Aria:
- If a temporary table was marked as crashed, it could never
  be deleted.
- Opening of a crashed temporary table gave an error message
  but the error was never forwarded to the caller which caused
  an assert() in my_ok()
- init_read_record() did mmap of all temporary tables, which is
  probably not a good idea as this area can potentially be
  very big. Changed code to only mmap internal temporary tables.
- mmap-ed tables where not unmapped in case of repair/optimize
  which caused bad data in table and crashes if the original
  table files where replaced with new ones (as the old mmap
  was still in place). Fixed by removing the mmap in case
  of repair.
- Cleaned up usage of code that disabled mmap in Aria

Problem was that in case of implicit rollback for alter table
Aria did try to run commit twice.

The test case for this is tricky to do in 10.2, so it will
be added to 10.4 as part of BACKUP STAGE testing.

           in where clause

The classes Item_func_isnottrue and Item_func_isnotfalse inherited the
implementation of the eval_not_null_tables method from the Item_func
class. As a result the not_null_tables_cache was set incorrectly for
the objects of these classes. It led to improper conversion of outer
joins to inner joins when the where clause of the processed query
contained IS NOT TRUE or IS NOT FALSE predicates. The coverted query
in many cases produced a wrong result set.

Do not check my_errno before it is set, check errno instead.
Also, do not check errno, if prior pread() did not fail.