Presubmit trybot fails a couple of times before finally succeeding.

Example: https://chromium-review.googlesource.com/c/chromium/tools/build/+/688235

From log:

Traceback (most recent call last):
  File "/b/s/w/ir/kitchen-checkout/scripts/slave/.recipe_deps/depot_tools/presubmit_support.py", line 1632, in <module>
    sys.exit(main())
  File "/b/s/w/ir/kitchen-checkout/scripts/slave/.recipe_deps/depot_tools/presubmit_support.py", line 1616, in main
    options.dry_run)
  File "/b/s/w/ir/kitchen-checkout/scripts/slave/.recipe_deps/depot_tools/presubmit_support.py", line 1359, in DoPresubmitChecks
    results += executer.ExecPresubmitScript(presubmit_script, filename)
  File "/b/s/w/ir/kitchen-checkout/scripts/slave/.recipe_deps/depot_tools/presubmit_support.py", line 1269, in ExecPresubmitScript
    result = eval(function_name + '(*__args)', context)
  File "<string>", line 1, in <module>
  File "<string>", line 236, in CheckChangeOnCommit
  File "<string>", line 104, in CommitChecks
  File "/b/s/w/ir/kitchen-checkout/scripts/slave/.recipe_deps/depot_tools/subprocess2.py", line 524, in check_output
    return check_call_out(args, stdout=PIPE, **kwargs)[0]
  File "/b/s/w/ir/kitchen-checkout/scripts/slave/.recipe_deps/depot_tools/subprocess2.py", line 487, in check_call_out
    returncode, args, kwargs.get('cwd'), out[0], out[1])
subprocess2.CalledProcessError: Command 'python scripts/slave/unittests/test_env.py' returned non-zero exit status 1
No compatible system-wide python-coverage package installed, and
setuptools is not installed either. Please obtain setuptools by:
Debian/Ubuntu:
  sudo apt-get install python-setuptools python-dev
OS X:
  https://pypi.python.org/pypi/setuptools#unix-including-mac-os-x-curl
Other:
  https://pypi.python.org/pypi/setuptools#installation-instructions
step returned non-zero exit code: 1