Fix to correct behaviour of find_and_fetch_row() for tables that have primary keys stored
in storage engines that support the fast method to fetch rows given a primary key. The
method uses position() to retrieve the key for a given record and rnd_pos() to position
the internal "cursor" at the row. Rnd_pos() returns the found record in table->record[0],
so the record has to be moved to table->record[1] for further processing after calling
find_and_fetch_row().