Test to ensure xdg_surface is not assigned non extending role

[i509VCB]

Per the documentation in xdg_wm_base.get_xdg_surface:

While xdg_surface itself is not a role, the corresponding surface may only be assigned a role extending xdg_surface, such as xdg_toplevel or xdg_popup

Talked with Simon about this on #wayland and he agrees that should exhibit a protocol error.

[RAOF]

I do want to extend the set of "this should raise a protocol error" tests we have. Do you know offhand what error should be raised in this case?

[i509VCB]

This might actually depend on what role object is being created.

If you create an xdg_surface and then a layer shell, probably an error on the layer shell.

But vice versa, with a layer shell, creating an xdg_surface would probably raise an error on the xdg_surface.