[OpenACC][CIR] Implement copyin/copyout/create lowering for compute/c… (#145976)
…ombined
This patch does the lowering of copyin (represented as a
acc.copyin/acc.delete), copyout (acc.create/acc.copyin), and create
(acc.create/acc.delete).
Additionally, it found a few problems with #144806, so it fixes those as
well.