gtk3-gi: add Gtk::ActionBar tests

test_pack is not working now...
TODO: free GIArgument(glist) as container

Gtk::ActionBar has been supported since Gtk+3 3.12.
ref: https://developer.gnome.org/gtk3/stable/GtkActionBar.html
(Gtk::ActionBar Gtk+3 3.12 document is not found. Why?)