GitLab

Remove these obsolete flags and associated functionality:
--branch
--netrc
--new-commit-flow
--jobs
--max-load

This depends on the internal recipe to stop using these flags (the
change for that is landing).

Bug: 1028600
Change-Id: Ideea791f06afabd1ae1674220eb458b10de5fd5e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1937367
Auto-Submit: Egor Pasko <pasko@chromium.org>
Commit-Queue: Benoit L <lizeb@chromium.org>
Reviewed-by: Benoit L <lizeb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719331}