[CI] Cinder upgrade testing

To gain visibility into how our upgrades affect existing Cinder
volumes, a new testing path is required.
This patch adds it.

Additionally, it refactors the repeated actions and ensures that
we wait for volume deletions as well.

Change-Id: Ic08d461e6fdf91c378a87860765a489c2f86d690
Related-Bug: #1904062