In the current plan enumeration/multi-planning architecture CBR can be thought of as an efficient alternative to mutli-planning. Following the approach how multi-planning fits into the query planner architecture, CBR is introduced as an implementation of two variants of mongo::PlannerInterface:

• classic_runtime_planner::ClassicPlannerInterface
• classic_runtime_planner_for_sbe::PlannerBase
  CBR is chosen as an alternative to the corresponding MultiPlanner classes.

The implementation will based on WRITING-25693.

The functionality is tested via a JS test.

Unit testing is not used because it would have to instantiate all the environment needed to call getExecutorFind. There is no single existing test that does that.