In SERVER-109762, we introduced a base implementation of 
BinaryEquiJoinEmbeddingNode which provided stub implementations of the virtual functions of QuerySolutionNode. We should implement these properly or determine that their implementations will never be invoked as we will generate this QuerySolution in a different codepath than the regular find executor.
 
The functions are:

• fetched()
• getFieldAvailability()

• sortedByDiskLoc()
• providedSorts()