This reverts commit 1e4dbf3f.

Reason for revert: unlikely but possible cause of http://shortn/_sgL4PqICVB

Original change's description:
> Add more git tracing.
> 
> 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/+/1888433
> Reviewed-by: Andrii Shyshkalov <tandrii@google.com>
> Commit-Queue: Erik Chen <erikchen@chromium.org>
> Auto-Submit: Erik Chen <erikchen@chromium.org>

TBR=danakj@chromium.org,tandrii@google.com,erikchen@chromium.org

Change-Id: I03b33bf1532212f83a6b89b1de32fafb6b8aafc4
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1891001Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>