test-cogl-pixel-buffer: Use the new name for CoglPixelArray
test-cogl-pixel-buffer: Use the new name for CoglPixelArray

Cogl has changed the name of the experimental CoglPixelArray API to
CoglPixelBuffer. This updates the test to reflect that so it will
continue to build.

spatulasnout/clutter,ebassi/clutter,kerrickstaley/clutter-vala,heysion/clutter-clone,heysion/clutter-clone,spatulasnout/clutter,GNOME/clutter,djdeath/clutter,heysion/clutter-clone,ebassi/clutter,jigpu/clutter,collects/clutter,heysion/clutter-clone,djdeath/clutter-multithreaded,heysion/clutter-clone,Distrotech/clutter,GNOME/clutter,dlespiau/clutter,ebassi/clutter,dlespiau/clutter,djdeath/clutter-android,djdeath/clutter,jigpu/clutter,collects/clutter,dlespiau/clutter,djdeath/clutter-android,GNOME/clutter,djdeath/clutter,djdeath/clutter-multithreaded,Distrotech/clutter,djdeath/clutter-android,collects/clutter,spatulasnout/clutter,Distrotech/clutter,Distrotech/clutter,spatulasnout/clutter,kerrickstaley/clutter-vala,Distrotech/clutter,jigpu/clutter,ebassi/clutter,jigpu/clutter,kerrickstaley/clutter-vala,ebassi/clutter,GNOME/clutter,djdeath/clutter,GNOME/clutter,djdeath/clutter-android,jigpu/clutter,djdeath/clutter,kerrickstaley/clutter-vala,djdeath/clutter-multithreaded,jigpu/clutter,collects/clutter,djdeath/clutter,djdeath/clutter-multithreaded,Distrotech/clutter,collects/clutter,spatulasnout/clutter,djdeath/clutter-android