fix test case, it previously verified incorrect behavior

fix test case, it previously verified incorrect behavior

2001-10-03  Havoc Pennington  <hp@redhat.com>

	* tests/testtextbuffer.c (logical_motion_tests): fix test case,
	it previously verified incorrect behavior

        Fixes for #61565

	* gtk/gtktextiter.c (gtk_text_iter_set_line): don't return lines
	off the end
	(_gtk_text_btree_get_iter_at_line_char): don't return lines off
	the end
	(_gtk_text_btree_get_iter_at_line_byte): don't return lines off
	the end
	(gtk_text_iter_forward_lines): if on the last line, move to end of
	it

	* gtk/gtktextbtree.c (_gtk_text_btree_last_could_contain_tag):
	don't return a line off the end