This CL adds more perf tracing to `git fetch` from bot_update.py and
git_cache.py

Change-Id: I9b69c60b6c81fc0c5f23f82fcc889b4d45a27556
Recipe-Nontrivial-Roll: build_limited_scripts_slave
Recipe-Nontrivial-Roll: build
Recipe-Nontrivial-Roll: infra
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1888433Reviewed-by: Andrii Shyshkalov <tandrii@google.com>
Commit-Queue: Erik Chen <erikchen@chromium.org>
Auto-Submit: Erik Chen <erikchen@chromium.org>