intel/compiler: Introduce simple IR analysis pass framework

intel/compiler: Introduce simple IR analysis pass framework

Motivated in detail in the source code.  The only piece missing here
from the analysis pass infrastructure is some sort of mechanism to
broadcast changes in the IR to all existing analysis passes, which
will be addressed by a future commit.  The analysis_dependency_class
enum might seem a bit silly at this point, more interesting dependency
categories will be defined later on.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>