use gtk_text_layout_invalidate_cache instead of cut-and-paste

use gtk_text_layout_invalidate_cache instead of cut-and-paste

2002-04-30  Havoc Pennington  <hp@redhat.com>

	* gtk/gtktextlayout.c (gtk_text_layout_real_free_line_data): use
	gtk_text_layout_invalidate_cache instead of cut-and-paste
	(gtk_text_layout_real_invalidate): always invalidate cache, even
	if the line has no stored line data. #78573

	* gtk/gtktextview.c (gtk_text_view_get_iter_location): add call to
	gtk_text_view_ensure_layout, #77388
	(gtk_text_view_get_iter_at_location): ditto
	(gtk_text_view_get_line_yrange): ditto
	(gtk_text_view_get_line_at_y): ditto