To enable aggregate analysis on changed files in BigQuery, conditionally
report them via an output property.

This CL causes a non-trivial roll only because of the sorting.

Recipe-Nontrivial-Roll: build
Bug: 1151655
Change-Id: Ie7a6c622196143c1aef07af9a9a356fb4202ea56
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2553349Reviewed-by: Andrii Shyshkalov <tandrii@google.com>
Commit-Queue: Nodir Turakulov <nodir@chromium.org>