Even though the PAUSE instruction latency was increased from
about 10 to 140 clock cycles in the Intel Skylake microarchitecture,
it seems to be optimal to reduce the amount of subsequently executed
PAUSE instructions not to 1/14, but to 1/2.

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

btr_lift_page_up(): Correct the incorrect condition.

page_validate(): Validate the page type.

page_validate(): Validate also the page type, and try to list all
errors that were encountered for the page, with a little more detail.

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.

The bug was that when long item-strings was converted to VARCHAR,
type_handler::string_type_handler() didn't take into account max
VARCHAR length.  The resulting Aria temporary table was created with
a VARCHAR field of length 1 when it should have been 65537. This caused
MariaDB to send impossible records to ma_write() and Aria reported
eventually the table as crashed.

Fixed by updating Type_handler::string_type_handler() to not create too long
VARCHAR fields. To make things extra safe, I also added checks in when
writing dynamic Aria records to ensure we find the wrong record during write
instead of during read.

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"

On some platforms, MY_RELAX_CPU() falls back to an atomic
memory operation, but my_cpu.h fails to include my_atomic.h.

The RDTSC instruction, which was introduced in the Intel Pentium,
has been used in MariaDB for a long time. But, the __rdtsc()
wrapper is not available by default in some x86 build environments.
The simplest solution seems to replace the inlined instruction
with a call to the wrapper function my_timer_cycles(). The overhead
for the call should not affect the measurement threshold.

On Windows and on AMD64, we will keep using __rdtsc() directly.

Starting with the Intel Skylake microarchitecture, the PAUSE
instruction latency is about 140 clock cycles instead of earlier 10.
On AMD processors, the latency could be 10 or 50 clock cycles,
depending on microarchitecture.

Because of this big range of latency, let us scale the loops around
the PAUSE instruction based on timing results at server startup.

my_cpu_relax_multiplier: New variable: How many times to invoke PAUSE
in a loop. Only defined for IA-32 and AMD64.

my_cpu_init(): Determine with RDTSC the time to run 16 PAUSE instructions
in two unrolled loops according, and based on the quicker of the two
runs, initialize my_cpu_relax_multiplier. This form of calibration was
suggested by Mikhail Sinyavin from Intel.

LF_BACKOFF(), ut_delay(): Use my_cpu_relax_multiplier when available.

ut_delay(): Define inline in my_cpu.h.

UT_COMPILER_BARRIER(): Remove. This does not seem to have any effect,
because in our ut_delay() implementation, no computations are being
performed inside the loop. The purpose of UT_COMPILER_BARRIER() was to
prohibit the compiler from reordering computations. It was not
emitting any code.

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.

Use correct preprocessor definition.
Do not compare socket value with FD_SETSIZE

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