Fix for walk() method of subqueries: always call the method on the subquery.

  fix for mem_total on windows
  report the time of the data snapshot

A bug in the code of the function key_or could lead to a situation
when performing of an OR operation for one index changes the result
the operation for another index. This bug is fixed with this patch.

Also corrected the specification and the code of the function 
or_sel_tree_with_checks.

In MariaDB, when running in ONLY_FULL_GROUP_BY mode,
the server produced in incorrect error message that there
is an aggregate function without GROUP BY, for artificially
created MIN/MAX functions during subquery MIN/MAX optimization.

The fix introduces a way to distinguish between artifially
created MIN/MAX functions as a result of a rewrite, and normal
ones present in the query. The test for ONLY_FULL_GROUP_BY violation
now tests in addition if a MIN/MAX function was part of a MIN/MAX
subquery rewrite.

In order to be able to distinguish these MIN/MAX functions, the
patch introduces an additional flag in Item_in_subselect::in_strategy -
SUBS_STRATEGY_CHOSEN. This flag is set when the optimizer makes its
final choice of a subuqery strategy. In order to make the choice
consistent, access to Item_in_subselect::in_strategy is provided
via new class methods.
******
Fix MySQL BUG#12329653

In MariaDB, when running in ONLY_FULL_GROUP_BY mode,
the server produced in incorrect error message that there
is an aggregate function without GROUP BY, for artificially
created MIN/MAX functions during subquery MIN/MAX optimization.

The fix introduces a way to distinguish between artifially
created MIN/MAX functions as a result of a rewrite, and normal
ones present in the query. The test for ONLY_FULL_GROUP_BY violation
now tests in addition if a MIN/MAX function was part of a MIN/MAX
subquery rewrite.

In order to be able to distinguish these MIN/MAX functions, the
patch introduces an additional flag in Item_in_subselect::in_strategy -
SUBS_STRATEGY_CHOSEN. This flag is set when the optimizer makes its
final choice of a subuqery strategy. In order to make the choice
consistent, access to Item_in_subselect::in_strategy is provided
via new class methods.

The function add_ref_to_table_cond missed updating the value of
join_tab->pre_idx_push_select_cond after having updated the value
of join_tab->select->pre_idx_push_select_cond.

(thanks viva64.com)

- Do not push index condition if we're using a triggered ref access.

update test results

The bug happened because in some cases the function JOIN::exec
did not save the value of TABLE::pre_idx_push_select_cond in
TABLE::select->pre_idx_push_select_cond for the sort table.

Noticed and fixed a bug in the function make_cond_remainder
that builds the remainder condition after extraction of an index
pushdown condition from the where condition. The code
erroneously assumed that the function make_cond_for_table left
the value of ICP_COND_USES_INDEX_ONLY in sub-condition markers.
Adjusted many result files from the regression test suite
after this fix .

The call of the virtual function cancel_pushed_idx_cond in the code of
the function test_if_skip_sort_order was misplaced when backporting the
fix for bug 58816.

Better error message if --log-bin is used without --log-bin-index

mysql-test/lib/v1/mysql-test-run.pl:
  Fixed that test doesn't abort if 'var' points to a deleted directory (common case when using --mem)
sql/mysqld.cc:
  Better error message if --log-bin is used without --log-bin-index

storage/myisam/mi_dbug.c:
  Added mutex to protect open table list while traversing it

- Remove the assert in replace_where_subcondition (the patch has explanation why)

- More test result updates (the errors are the same, the difference is that "at row X" became "at row Y" due to
  queries with semi-joins producing select results in different order)

- More test result updates

- semijoin=on
- firstmatch=on
- loosescan=on

Analysis:
Equality propagation propagated the constant '7' into
args[0] of the Item_in_optimizer that stands for the
"< ANY" predicate. At the same the min/max subquery
rewrite swapped the order of the left and right operands
of the "<" predicate, but used Item_in_subselect::left_expr.

As a result, when the <ANY predicate is executed early in the
execution phase as a contant condition, instead of a constant
right (swapped) argument of the < predicate, there was a field
(t3.a). This field had no data, since the whole predicate is
considered constant, and it is evaluated before any tables are
read. Having junk in the field row buffer produced wrong result

Solution:
Fix create_swap to pick the correct Item_in_optimizer left
argument.

The problem was that merged views has its own nest_level numbering =>
when we compare nest levels we should take into considiration basis (i.e. 0 level),
if it is different then nest levels are not comparable.

Fixed a bug in select_describe.
Adjusted results for affected test cases.

- Make eliminate_tables_for_list() take into account that it is not possible
  to eliminate a table if it is used in the upper-side ON expressions. Example:

    xxx JOIN (t1 LEFT JOIN t2 ON cond ) ON func(t2.columns)

  Here it would eliminate t2 which is not possible because of use of t2.columns.