testplans: Update v1 converter to support multi-dut tests.

Design Doc: go/cros-infra:multi-dut-cq-dd

BUG=b:281011516
TEST=unit test

Cq-Depend: chromium:5017053
Change-Id: I60df59c4b8436939a7c8dc29cf44570b938b9f98
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/5002322
Reviewed-by: Andrew Lamb <andrewlamb@chromium.org>
Tested-by: Ming Kong <mingkong@google.com>
Commit-Queue: ChromeOS Auto Retry <chromeos-auto-retry@chromeos-bot.iam.gserviceaccount.com>
4 files changed