test-texture-3d: Add a test for multi-texturing 3D and 2D textures
test-texture-3d: Add a test for multi-texturing 3D and 2D textures

The ARBfp fragend has a bug when the texture combine string references
another texture unit where it will use the texture type of the current
layer rather than the texture type of the layer the string refers to.
This patch adds a small test which demonstrates that.

Reviewed-by: Robert Bragg <12e9293ec6b30c7fa8a0926af42807e929c1684f@linux.intel.com>

Distrotech/cogl,djdeath/cogl-android,djdeath/cogl,gcampax/cogl,Distrotech/cogl,gcampax/cogl,djdeath/cogl-android,Distrotech/cogl,gcampax/cogl,Distrotech/cogl,djdeath/cogl-android,djdeath/cogl,djdeath/cogl,gcampax/cogl