In order to emulate D3D11 behaviour when a resource is not bound,
we use specialization constants. This requires further changes in
the shader compiler.
Fixes a few bottlenecks that were encountered in the Cascading Shadow
Maps demo from the Microsoft SDK. Performance is now slightly better
than wined3d with CSMT, MESA_NO_ERROR and mesa_glthread enabled.
When invalidating a constant buffer, the descriptor was not
updated, which usually led to the wrong resource being used
and could also cause crashes.
This fix also includes resource tracking for shader resources
on the graphics pipeline. The code needs to be made compatible
with the compute pipeline as well.
