Add test coverage of transaction in post transation callback

Alex Pottrequested to merge
issue/drupal-3447097:3447097-transactionnamenonuniqueexception-a-transaction-11.1.x into 11.1.x

(cherry picked from commit 08ada21aa2829c3cb360d33ac6f9839d0bfa3777)

Closes #3447097

Merge request reports