Change a unit test to exempt boards from hwtests.

This changes a unit test to exempt boards that have
"config.hwqual=false" from hardware tests configured.

BUG=chromium:571645
TEST=unit tests & trybot run

Change-Id: I31c0ae749f4e62572f9c650db6c9b011864892e0
Reviewed-on: https://chromium-review.googlesource.com/319643
Commit-Ready: Xixuan Wu <xixuan@chromium.org>
Tested-by: Xixuan Wu <xixuan@chromium.org>
Reviewed-by: Mungyung Ryu <mkryu@google.com>
3 files changed