Add fwb_tries=1 steps on firmware CorruptFwA and CorruptBothFwAB tests.

Adding these steps increase the test coverage:
 - Normal mode, fwb_tries=1, fwA=Broken, fwB=Normal => fwB boot
 - Developer mode, fwb_tries=1, fwA=Broken, fwB=Normal => fwB boot
 - Normal mode, fwb_tries=1, fwA=Broken, fwB=Broken => recovery boot
 - Developer mode, fwb_tries=1, fwA=Broken, fwB=Broken => recovery boot

BUG=chromium-os:22598
TEST=run_remote_tests.sh --remote=$REMOTE_IP -a "xml_config=$OVERLAY_XML \
        servo_vid=0x18d1 servo_pid=0x5001" firmware_CorruptFwA
     run_remote_tests.sh --remote=$REMOTE_IP -a "xml_config=$OVERLAY_XML \
        servo_vid=0x18d1 servo_pid=0x5001" firmware_CorruptBothFwAB

Change-Id: I02269ce1fbc124f4721b1fd8e581fa8c15bdfdb4
Reviewed-on: https://gerrit.chromium.org/gerrit/12064
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Rajesh Chenna <rchenna@chromium.org>
Commit-Ready: Tom Wai-Hong Tam <waihong@chromium.org>
Tested-by: Tom Wai-Hong Tam <waihong@chromium.org>
2 files changed