[test-shader] Fix some of the shaders to use premultiplied colors
[test-shader] Fix some of the shaders to use premultiplied colors

Texture data is now in premultiplied format and the shader should
output a premultiplied color if the default blend mode is being
used. Shaders that directly manipulate the rgb values now
unpremultiply and premultiply again afterwards.

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