test_platform: use build ID to construct the resource identity

As this schema is designed for internal team, we could replace
the uuid by build ID, which we did not want to expose to the
external users.

BUG=chromium:1085958
TEST=./generate.sh

Change-Id: I91072c38861240dd1ecdabe11c4239574b63c371
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/proto/+/2229847
Commit-Queue: Xinan Lin <linxinan@chromium.org>
Tested-by: Xinan Lin <linxinan@chromium.org>
Auto-Submit: Xinan Lin <linxinan@chromium.org>
Reviewed-by: Alex Zamorzaev <zamorzaev@chromium.org>
2 files changed