// A yield has occurred, but there still may not be a 'yieldable'. This is true, for example,
    // when executing a getMore for the slot-based execution engine. SBE uses the "locks internally"
    // lock policy, and therefore the getMore code path does not acquire any db_raii object. As a
    // result, there is no db_raii object to restore here when executing a getMore against a cursor
    // using SBE.