tests: fix test with glib 2.68 re GLocalFile
tests: fix test with glib 2.68 re GLocalFile

Since 2.68 Gio.File.new_for_path("") returns a GDummyFile instead of
a GLocalFile. We don't really care since we just want to test that there
is a name despite the type not being in the gir, so just pass a potentially
valid path instead.

GNOME/pygobject,GNOME/pygobject,GNOME/pygobject