The drawing code from test_invalid_texture_layers which draws a
rectangle, a polygon and a vertex buffer has been split out to
separate function. test_using_all_layers now also uses this so that it
will also test the other two primitives. This causes the test to fail
when all of the layers are drawn using a vertex buffer.
http://bugzilla.openedhand.com/show_bug.cgi?id=2132