Class "Timer" is not being used and the related unit tests
are failing quite often in py38 CI job.
Conflicts:
neutron/tests/unit/common/test_utils.py
Change-Id: Ib1d8f2f4adeadbd59c3dccc7be1546baedc4b978
Related-Bug: #1922563
(cherry picked from commit 48bce78d1a)