isolate: pull uploading of deps out of exparchive main.
isolate: pull uploading of deps out of exparchive main.

BUG=692940

Review-Url: https://codereview.chromium.org/2986773002

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