tests: Separate lister instantiations
Prior to this commit, all listers were instantiated at the same time even if only one was needed. This commit separates those instantiations.
The only drawback to this is the db model initialization which now happens at each lister instantiation. This can be dealt with if needed at another time though.
Depends on !151 (closed)
Test Plan
tox
Migrated from D3860 (view on Phabricator)