GeoMatchExpression::equivalent and GeoNearMatchExpression::equivalent should check for equivalence in their respective GeoExpression and GeoNearExpression

GeoMatchExpression::equivalent and GeoNearMatchExpression::equivalent currently compares the raw BSON objects (_rawObj), which does not equate to fully-correct equivalence between the match expressions. We should implement equivalence in the fully-correct sense that the GeoExpression and GeoNearExpression (_query) are checked for full equivalence as well.