[cas] add dump-stats-json flag to `archive`
[cas] add dump-stats-json flag to `archive`

Bug: 1110569
Change-Id: I8efd1cc17d68dbb0685d72d20d0d2ab1e7d47f72
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/2395938
Auto-Submit: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Commit-Queue: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Reviewed-by: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>

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