Now that the presubmit system no longer supports Python 2 we can remove
support for it from the presubmit system tests. This change removes all
references to sys.version_info from this file.
This also fixes an unclosed file warning that suddenly appeared and
was stopping this change from landing.
Bug: 1207012
Change-Id: Ib74e9009b9d5cea0caf37c88e3258e9dd818f269
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4522416
Reviewed-by: Aravind Vasudevan <aravindvasudev@google.com>
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>