autotest: reverse order of after-run_once hooks.

Hooks can be registered to run before and after run_once().  Execute the
"after" hooks in reverse order, so that before/after pairs work like a
stack.  This makes log entries look more sensible.

BUG=None
TEST=./test_unittest.py

Change-Id: Id88981552e442e7035b3717f43fcdc4f4c5245b0
Previous-Reviewed-on: https://chromium-review.googlesource.com/277037
(cherry picked from commit 651083877f0c30759073e5d860d07bb01db347fb)
Reviewed-on: https://chromium-review.googlesource.com/285546
Reviewed-by: Ilja Friedel <ihf@chromium.org>
Commit-Queue: Christopher Grant <cjgrant@chromium.org>
Tested-by: Christopher Grant <cjgrant@chromium.org>
1 file changed