tests: Use g_ptr_array_set_free_func() rather than manual free()
tests: Use g_ptr_array_set_free_func() rather than manual free()

We don’t need to free array elements manually.

Signed-off-by: Philip Withnall <29c2a2ac2a854b9cf047275aa9de346d096be2e0@endlessm.com>

endlessm/glib,endlessm/glib,endlessm/glib,endlessm/glib,endlessm/glib