intel: Allocate prog_data::[pull_]param deeper inside the compiler

intel: Allocate prog_data::[pull_]param deeper inside the compiler

Now that we're always growing the param array as-needed, we can
allocate the param array in common code and stop repeating the
allocation everywere.  In order to keep things sane, we ralloc the
[pull_]param array off of the compile context and then steal it back
to a NULL context later.  This doesn't get us all the way to where
prog_data::[pull_]param is purely an out parameter of the back-end
compiler but it gets us a lot closer.

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