autotest: add logging for hot machine.

When a machine remains hot we need more information if there is
a process keeping it warm.

BUG=chromium:417517
TEST=pylint

Change-Id: I8cca3c9c4e3e42f2322087aa15a997c9077495b0
Reviewed-on: https://chromium-review.googlesource.com/226776
Commit-Queue: Ilja Friedel <ihf@chromium.org>
Tested-by: Ilja Friedel <ihf@chromium.org>
Reviewed-by: Haixia Shi <hshi@chromium.org>
1 file changed