Alternate version of MySQL's fix for BUG#49453.
Alternate version of MySQL's fix for BUG#49453.

The cause of the crash is sj_nest->sj_subq_pred->unit->first_select()->item_list
contains "stale" items for the second execution. By "stale" I mean that they have
item->fixed==FALSE, and they are Item_field object instead of Item_direct_view_ref.

The solution is to use sj_nest->sj_subq_pred->unit->first_select()->ref_pointer_array.
Surprisingly, that array contains items that are ok.

Oracle team has introduced and is using NESTED_JOIN::sj_inner_exprs, but we go without that
and always copy the ref_pointer_array.



flynn1973/mariadb-aix,davidl-zend/zenddbi,flynn1973/mariadb-aix,flynn1973/mariadb-aix,natsys/mariadb_10.2,ollie314/server,natsys/mariadb_10.2,slanterns/server,ollie314/server,davidl-zend/zenddbi,natsys/mariadb_10.2,ollie314/server,ollie314/server,davidl-zend/zenddbi,davidl-zend/zenddbi,flynn1973/mariadb-aix,flynn1973/mariadb-aix,flynn1973/mariadb-aix,natsys/mariadb_10.2,natsys/mariadb_10.2,ollie314/server,natsys/mariadb_10.2,davidl-zend/zenddbi,davidl-zend/zenddbi,natsys/mariadb_10.2,flynn1973/mariadb-aix,davidl-zend/zenddbi,davidl-zend/zenddbi,flynn1973/mariadb-aix,ollie314/server,davidl-zend/zenddbi,ollie314/server,ollie314/server,natsys/mariadb_10.2,flynn1973/mariadb-aix,ollie314/server,ollie314/server,natsys/mariadb_10.2,flynn1973/mariadb-aix,davidl-zend/zenddbi,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,natsys/mariadb_10.2,natsys/mariadb_10.2