Performance regressed by 31% in one VP2020/Creo subtest because
the draw_always_async flag wasn't implemented correctly. Remove it
instead of fixing it.
While removing it, I noticed that our DrawIndirect async conditions
were incorrect. I fixed them.
Fixes: 3b897719e6 - glthread: add ctx->GLThread.draw_always_async to simplify draw checking
Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21566>