au_test_harness: Deprecate real_au_worker

Traced it all the way back to ctest.py use cases, and nowhere
real_au_worker has been used. cros flash should be used instead, but
since there is no use case for it right now, just deprecate it. It helps
with the cleanup of devserver.

BUG=chromium:872441
TEST=pfq-tryjob

Change-Id: I61e8503ea29c766d4582eecd8b0dbc80f06e69d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/1808406
Reviewed-by: Daniel Wang <wonderfly@google.com>
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
Reviewed-by: Alex Zamorzaev <zamorzaev@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Amin Hassani <ahassani@chromium.org>
Commit-Queue: Amin Hassani <ahassani@chromium.org>
4 files changed