[bbagent]: pull out stopinfo
[bbagent]: pull out stopinfo

Bug:1346754
Change-Id: I19ee966a3fddf73939b5ae56306c618886d15308
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/3803985
Commit-Queue: Yulan Lin <fa22fbbce8ab65d96ec9925b9c61a0c0692eb649@google.com>
Reviewed-by: Chan Li <332b6c56634d0f63001046c664a2370006a02420@chromium.org>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go