It's not connected up to anything at the moment, and even if I do enable
it for crocus HSW it only shaves 3 instructions off of one particular VS
in an old synthetic benchmark, not affecting anything else in shader-db.
I don't think anyone will care to ever fix or port this to NIR, let's just
retire it.
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21353>