If the slot-based execution engine is enabled on a particular shard, then the planner may produce plans that involve the SHARDING_FILTER QuerySolutionNode. Today, the system will simply uassert() if it encounters a SHARDING_FILTER node when converting the QuerySolution to an SBE plan. We need to extend SBE to be capable of doing shard-filtering at runtime in order for it to be used in sharded clusters.