pytest: verify_root_partition: support remote DUT

Support verifying root partition on remote DUT.

BUG=None
TEST=manual

Change-Id: I4b182e95a4cc18277a7c09a533481c0c40839366
Reviewed-on: https://chromium-review.googlesource.com/394487
Commit-Ready: Wei-Han Chen <stimim@chromium.org>
Tested-by: Wei-Han Chen <stimim@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
2 files changed