praefect: fix race condition on logger
TestAddRepositories_Exec
uses a single logger that is passed to each
test case, which are run in parallel. This causes intermittent failures
on the race-go
test job, as multiple test goroutines attempt to update
the logger.
Fix this by creating a new logger for each test case.
Closes #4473 (closed) #4457 (closed)
Edited by Will Chandler (ex-GitLab)