In rare cases, we can get into situations where the tracking of read/
written resources triggers a flush of the current batch.

To handle that, (1) take a reference to the current batch, so it doesn't
disappear under us, and (2) check after resource tracking whether the
current batch was flushed.  If it is, we have to re-do the resource
tracking, but since we have a fresh batch, it should not get flushed the
second time around.

Closes: #3160


Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <!5634>