textiter: remove recursivity of find_by_log_attrs()

textiter: remove recursivity of find_by_log_attrs()

find_by_log_attrs() was a recursive function. It is replaced by an
iteration.

The already_moved_initially parameter was TRUE only for the recursive
call, so the paramater is removed.

There is also a small cleanup of the find_visible_by_log_attrs()
(remove trailing spaces, fix indentation).

There is still a part to optimize for a later commit.

https://bugzilla.gnome.org/show_bug.cgi?id=629129