freedreno/ir3: Sync some new changes from envytools.

freedreno/ir3: Sync some new changes from envytools.

With this I also brought in a few new control flow instruction disasm
tests that I'd made back when I wrote the disasm test, but which were too
far from correct to include until now.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4857>