fix wsrep not to crash when started disabled

that didn't quite work, WITH_PARTITION_STORAGE_ENGINE
was not undefined

from engines that we don't need to merge from
a third-party repository on a regular basis

you the progress of inplace alter table and row log buffer usage

-    (x 100%, it's 4-digit. 10000 means 100.00%)
-    Innodb_onlineddl_rowlog_rows
       Shows how many rows are stored in row log buffer.
-    Innodb_onlineddl_rowlog_pct_used
       Shows row log buffer usage in percent ( *100%, it's 4-digit. 10000 means 100.00% ).
-    Innodb_onlineddl_pct_progress
       Shows the progress of inplace alter table. It might
       be not so accurate because inplace alter is highly
       depend on disk and buffer pool status.
       But still it is useful and better than nothing.

-    Add some log for inplace alter table
       XtraDB/InnoDB will print some message before and
       after doing some task.

-- innodb-wl5522-debug-zip (path differences win/unix)
-- innodb_defragment_fill_factor (stabilise)
-- innodb_force_pk (case difference win/unix)

Updated 33_scripts__mysql_create_system_tables__no_test.dpatch
to reflect user.default_role.

[re-commit in git]
Second variant of the fix: reduce the scope of 'role' variable

[Re-commit in git]
Don't check the value of 'role' variable in the cases where we don't need
it. (it may be marked as uninitialized and we get a runtime error).

The problem was that the internal temporary table created
for information_schema overflow to MyISAM because it has
a row width of > 3000 characters, which filled the in memory
temporary tables.
Fix was to increase size for the heap table.

on binlog_innodb_row test.

result of innodb_sys_index test.

Fixed test failures seen on defragment tests, innodb.innodb-wl5522-debug-zip
and innodb.innodb_bug12902967.

SHOW COLUMNS and SHOW KEYS commands fill IS_table_read_plan
in a special way - they don't set or use lookup_field_vals
member.

Added a "trivial_show_command" flag that signals that
lookup_field_vals has no valid data, made EXPLAIN code honor it.

  MDEV-6656: Test wsrep.variables hangs

  Analysis: wsrep_applier_thread shutdown signaling does not always work
  correctly causing a timing problem where main thread is waiting in a
  condition variable a signal that all worker threads to end.