arbfp: Copy pipelines used as cache keys
arbfp: Copy pipelines used as cache keys

We are currently using a pipeline as a key into our arbfp program cache
but because we weren't making a copy of the pipelines used as keys there
were times when doing a lookup in the cache would end up trying to
compare a lookup key with an entry key that would point to invalid
memory.

Note: the current approach isn't ideal from the pov that that key
pipeline may reference some arbitrarily large user textures will now be
kept alive indefinitely. The plan to improve on this is that we will
have a mechanism to create a special "key pipeline" which will derive
from the default Cogl pipeline (to avoid affecting the lifetime of
other pipelines) and only copy state from the original pipeline that
affects the arbfp program and will reference small dummy textures
instead of potentially large user textures.

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