The RollbackTestFixture (and RollBackTestFixtureDeluxe) supports passing in an optional ReplSetTest fixture. This requires the caller to provide a fully initialized ReplSetTest instance that meets the requirements of the RollbackTest fixture.

In some scenarios, we may want to simply add a startup parameter to the default replica set provided by performStandardSetup() without reproducing the entire default configuration. It would be convenient to be able to pass in an initial nodeOptions that would be used by performStandardSetup().