dict_stats_exec_sql(): Refuse the operation if shutdown has been
initiated.

The real fix would be to update the persistent statistics as part
of the data dictionary transactions. To do this, we should move the
storage of InnoDB persistent statistics to the InnoDB data files,
and maybe also remove the InnoDB data dictionary.

Item_param::set_value() did not set Item::collation and
Item_param::str_value_ptr.str_charset properly. So both
metadata and data for OUT parameters were sent in a wrong
way to the client.

This patch removes the old implementation of Item_param::set_value()
and rewrites it using Type_handler::Item_param_set_from_value(),
so now setting IN and OUT parameters share the a lot of code.

1. Item_param::set_str() now:
  - accepts two additional parameters fromcs, tocs
  - sets str_value_ptr, to make sure it's always in sync with str_value,
    even without Item_param::convert_str_value()
  - does collation.set(tocs, DERIVATION_COERCIBLE),
    to make sure that DTCollation is valid even without
    Item_param::convert_str_value()

2. Item_param::set_value(), which is used to set OUT parameters,
   now reuses Type_handler::Item_param_set_from_value().

3. Cleanup: moving Item_param::str_value_ptr to private,
   as it's not needed outside.

4. Cleanup: adding a new virtual method
   Settable_routine_parameter::get_item_param()
   and using it a few new DBUG_ASSERTs, where
   Item_param cannot appear.

After this change:
1. Assigning of IN parameters works as before:
a. Item_param::set_str() is called and sets the value as a binary string
b. The original value is sent to the query used for binary/general logging
c. Item_param::convert_str_value() converts the value from the client
   character set to the connection character set

2. Assigning of OUT parameters works in the new way:
a. Item_param::set_str() and sets the value
   using the source Item's collation, so both Item::collation
   and Item_param::str_value_ptr.str_charset are properly set.
b. Protocol_binary::send_out_parameters() sends the
   value to the client correctly:
   - Protocol::send_result_set_metadata() uses Item::collation.collation
     (which is now properly set), to detect if conversion is needed,
     and sends a correct collation ID.
   - Protocol::send_result_set_row() calls Type_handler::Item_send_str(),
     which uses Item_param::str_value_ptr.str_charset
     (which is now properly set) to actually perform the conversion.

Also, MDEV-14317 When ALTER TABLE is aborted, do not write garbage pages to data files

As pointed out by Shaohua Wang, the merge of MDEV-13328 from
MariaDB 10.1 (based on MySQL 5.6) to 10.2 (based on 5.7)
was performed incorrectly.

Let us always pass a non-NULL FlushObserver* when writing
to data files is desired.

FlushObserver::is_partial_flush(): Check if this is a bulk-load
(partial flush of the tablespace).

FlushObserver::is_interrupted(): Check for interrupt status.

buf_LRU_flush_or_remove_pages(): Instead of trx_t*, take
FlushObserver* as a parameter.

buf_flush_or_remove_pages(): Remove the parameters flush, trx.
If observer!=NULL, write out the data pages. Use the new predicate
observer->is_partial() to distinguish a partial tablespace flush
(after bulk-loading) from a full tablespace flush (export).
Return a bool (whether all pages were removed from the flush_list).

buf_flush_dirty_pages(): Remove the parameter trx.

MDEV-14435 Different UNSIGNED flag of out user variable for YEAR parameter for direct vs prepared CALL

is set to true, as it should.

Copy and modify original io_win.h header file to a different location
(as we cannot patch anything in submodule). Make sure modified header is
used.

        Result unescaping added.

This is caused by following change:

commit 95d29c99f01882ffcc2259f62b3163f9b0e80c75
Author: Marko Mäkelä <marko.makela@oracle.com>
Date:   Tue Nov 27 11:12:13 2012 +0200

    Bug#15920445 INNODB REPORTS ER_DUP_KEY BEFORE CREATE UNIQUE INDEX COMPLETED

    There is a phase during online secondary index creation where the index has
    been internally completed inside InnoDB, but does not 'officially' exist yet.
    We used to report ER_DUP_KEY in these situations, like this:

    ERROR 23000: Can't write; duplicate key in table 't1'

    What we should do is to let the 'offending' operation complete, but report an
    error to the
    ALTER TABLE t1 ADD UNIQUE KEY (c2):

    ERROR HY000: Index c2 is corrupted
    (This misleading error message should be fixed separately:
    Bug#15920713 CREATE UNIQUE INDEX REPORTS ER_INDEX_CORRUPT INSTEAD OF DUPLICATE)

    row_ins_sec_index_entry_low(): flag the index corrupted instead of
    reporting a duplicate, in case the index has not been published yet.

    rb:1614 approved by Jimmy Yang

Problem is that after we have found duplicate key on primary key
we continue to get necessary gap locks in secondary indexes to
block concurrent transactions from inserting the searched records.
However, search from unique index used in foreign key constraint
could return DB_NO_REFERENCED_ROW if INSERT .. ON DUPLICATE KEY UPDATE
does not contain value for foreign key column. In this case
we should return the original DB_DUPLICATE_KEY error instead
of DB_NO_REFERENCED_ROW.

Consider as a example following:

create table child(a int not null primary key,
b int not null,
c int,
unique key (b),
foreign key (b) references
parent (id)) engine=innodb;

insert into child values (1,1,2);

insert into child(a) values (1) on duplicate key update c = 3;

Now primary key value 1 naturally causes duplicate key error that will be
stored on node->duplicate. If there was no duplicate key error, we should
return the actual no referenced row error. As value for column b used in
both unique key and foreign key is not provided, server uses 0 as a
search value. This is naturally, not found leading to DB_NO_REFERENCED_ROW.
But, we should update the row with primay key value 1 anyway as
requested by on duplicate key update clause.

Fix of nondebuging version issue

This problem was earlier fixed in bb-10.2-ext.
Adding tests only.

The patch for MDEV-11146 fixed this problem earlier.
Only adding tests from the report.

MDEV-12846 sql_mode=ORACLE: using Oracle-style placeholders in direct query execution makes the server crash

than the query itself

ACL checks were not properly supported for tables used in CTE
specifications. This patch fixes the problem.

        Check for the empty 'coordinates' array.

Reinit internal state of select_unit before using to correctly run it after first time.

MDEV-13723: Server crashes in ha_heap::find_unique_row or Assertion `0' failed in st_select_lex_unit::optimize with INTERSECT

With INTERSECT/EXCEPT fact that subquery item of IN/ALL/ANY was not assigned value does not mean that temporary table used for calculating unit is empty (records could be deleted).

        Character bigger than 0x60 wasn't handled properly
        inside a numeric constant.

This patch effectively blocks the optimization that uses multiple
equalities for ORDER BY to remove tmp table in the case when
the first table happens to be the result of materialization of
a semi-join nest. Currently there is no code at the execution level
that would support the optimization in this case.

rec_get_offsets_func(): Relax a bogus debug assertion.
It would fail when we are operating on a copied prefix
of a node pointer record.