With the merge of WT-8601, WT logging-based testing (including backup and recovery) has been reduced, as test programs configuring transactional timestamps are less likely to configure logging (and vice-versa), and even when both are configured, less testing will be done, for example, format will no longer do repeatable read testing of logged files because it's based on timestamps.

The simplest fix is probably to update some test programs to run with mixed logged and non-logged tables as MongoDB Server does, doing appropriate repeatable read testing for each. That would give us better testing of the oplog/collection combination found in MongoDB Server and is probably itself a useful change.