MDEV-12873 InnoDB SYS_TABLES.TYPE incompatibility for PAGE_COMPRESSED=YES in MariaDB 10.2.2 to 10.2.6

Remove the SHARED_SPACE flag that was erroneously introduced in
MariaDB 10.2.2, and shift the SYS_TABLES.TYPE flags back to where
they were before MariaDB 10.2.2. While doing this, ensure that
tables created with affected MariaDB versions can be loaded,
and also ensure that tables created with MySQL 5.7 using the
TABLESPACE attribute cannot be loaded.

MariaDB 10.2.2 picked the SHARED_SPACE flag from MySQL 5.7,
shifting the MariaDB 10.1 flags PAGE_COMPRESSION, PAGE_COMPRESSION_LEVEL,
ATOMIC_WRITES by one bit. The SHARED_SPACE flag would always
be written as 0 by MariaDB, because MariaDB does not support
CREATE TABLESPACE or CREATE TABLE...TABLESPACE for InnoDB.

So, instead of the bits AALLLLCxxxxxxx we would have
AALLLLC0xxxxxxx if the table was created with MariaDB 10.2.2
to 10.2.6. (AA=ATOMIC_WRITES, LLLL=PAGE_COMPRESSION_LEVEL,
C=PAGE_COMPRESSED, xxxxxxx=7 bits that were not moved.)

PAGE_COMPRESSED=NO implies LLLLC=00000. That is not a problem.

If someone created a table in MariaDB 10.2.2 or 10.2.3 with
the attribute ATOMIC_WRITES=OFF (value 2; AA=10) and without
PAGE_COMPRESSED=YES or PAGE_COMPRESSION_LEVEL, the table should be
rejected. We ignore this problem, because it should be unlikely
for anyone to specify ATOMIC_WRITES=OFF, and because 10.2.2 and
10.2.2 were not mature releases. The value ATOMIC_WRITES=ON (1)
would be interpreted as ATOMIC_WRITES=OFF, but starting with
MariaDB 10.2.4 the ATOMIC_WRITES attribute is ignored.

PAGE_COMPRESSED=YES implies that PAGE_COMPRESSION_LEVEL be between
1 and 9 and that ROW_FORMAT be COMPACT or DYNAMIC. Thus, the affected
wrong bit pattern in SYS_TABLES.TYPE is of the form AALLLL10DB00001
where D signals the presence of a DATA DIRECTORY attribute and B is 1
for ROW_FORMAT=DYNAMIC and 0 for ROW_FORMAT=COMPACT. We must interpret
this bit pattern as AALLLL1DB00001 (discarding the extraneous 0 bit).

dict_sys_tables_rec_read(): Adjust the affected bit pattern when
reading the SYS_TABLES.TYPE column. In case of invalid flags,
report both SYS_TABLES.TYPE (after possible adjustment) and
SYS_TABLES.MIX_LEN.

dict_load_table_one(): Replace an unreachable condition on
!dict_tf2_is_valid() with a debug assertion. The flags will already
have been validated by dict_sys_tables_rec_read(); if that validation
fails, dict_load_table_low() will have failed.

fil_ibd_create(): Shorten an error message about a file pre-existing.

Datafile::validate_to_dd(): Clarify an error message about tablespace
flags mismatch.

ha_innobase::open(): Remove an unnecessary warning message.

dict_tf_is_valid(): Simplify and stricten the logic. Validate the
values of PAGE_COMPRESSION. Remove error log output; let the callers
handle that.

DICT_TF_BITS: Remove ATOMIC_WRITES, PAGE_ENCRYPTION, PAGE_ENCRYPTION_KEY.
The ATOMIC_WRITES is ignored once the SYS_TABLES.TYPE has been validated;
there is no need to store it in dict_table_t::flags. The PAGE_ENCRYPTION
and PAGE_ENCRYPTION_KEY are unused since MariaDB 10.1.4 (the GA release
was 10.1.8).

DICT_TF_BIT_MASK: Remove (unused).

FSP_FLAGS_MEM_ATOMIC_WRITES: Remove (the flags are never read).

row_import_read_v1(): Display an error if dict_tf_is_valid() fails.