Post-push fix.

10.5 MDEV-30775 fix inserts just opened tablespace just after the element
which fil_system.space_list_last_opened points to.

In MDEV-25223 fil_system_t::space_list was changed from UT_LIST to
ilist. ilist<...>::insert(iterator pos, reference value) inserts element
to list before pos.

But it was not taken into account during 10.5->10.6 merge in
85cbfaef, and the fix
does not work properly, i.e. it inserted just opened tablespace to the
position preceding fil_system.space_list_last_opened.