intel: Rewrite the world of push/pull params

intel: Rewrite the world of push/pull params

This moves us away to the array of pointers model and onto a model where
each param is represented by a generic uint32_t handle.  We reserve 2^16
of these handles for builtins that get generated by somewhere inside the
compiler and have well-defined meanings.  Generic params have handles
whose meanings are defined by the driver.

The primary downside to this new approach is that it moves a little bit
of the work that we would normally do at compile time to draw time.  On
my laptop this hurts OglBatch6 by no more than 1% and doesn't seem to
have any measurable affect on OglBatch7.  So, while this may come back
to bite us, it doesn't look too bad.

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>