I've observed today that V8 builder spends ~1 minute to download
a bunch of lose files representing tags[1]. This CL should
shrink ~2K files to just 72.

[1]
https://logs.chromium.org/logs/v8/buildbucket/cr-buildbucket.appspot.com/8865281064556718960/+/steps/initialization/0/steps/bot_update/0/stdout

R=jochen@chromium.org, machenbach@chromium.org

Change-Id: Ib8f245e6ed67ea91b53b22a8e4f729ab899a1cbc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2502476
Auto-Submit: Andrii Shyshkalov <tandrii@google.com>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>