Rather than using builder magic (implicitly lowered on emit), add actual pseudo
operations (explicitly lowered before encoding). In theory this is slower, I
doubt it matters. This makes the instruction aliases first-class for IR prining
and machine inspection, which will make optimization passes easier to write.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16268>
