st/texture: allow compute blits for (some) non-finalized textures
this yields sizable perf improvements in some cases
KHR-GL46.copy_image.functional timing (zink+anv-icl):
before MESA_LOADER_DRIVER_OVERRIDE=zink ./glcts -n 74.77s user 76.44s system 33% cpu 7:32.38 total
after MESA_LOADER_DRIVER_OVERRIDE=zink ./glcts -n 69.95s user 68.84s system 33% cpu 6:51.54 total
Edited by Mike Blumenkrantz