freedreno/ir3: shader-cache
With mh31 and a couple play store games, a cache-hit startup is around 66-75% percent of a cold-cache (or no-shader-cache) startup time, which seems like a useful improvement.
I've rebased this to not be on top of !5595 (merged) for easier review, but !5595 (merged) needs to land first to prevent a couple CI regressions.
Edited by Rob Clark