Fix to several issues around set result operators (Contains etc)

[maumar]

#8524 - Query: data corruption for queries with set result operators (Concat/Union etc) and collection navigations
#8525 - Query: compilation error for queries with navigations inside set result operators and Count
#9004 - Query: compilation error for queries with Concat on two entities and Count

Problem was that for set result operators we always need to materialize both sets, even if they are wrapped around scalar result operator (e.g. Count). This is needed because set result operators are currently performed on the client.

Also, we need to inject MaterializeCollectionNavigation calls into set result operators, so that the IQuerySource that is the argument to the set operator is wrapped in its own query source.

Also fixed some minor bugs in the MaterializeCollectionNavigation injector, which surfaced once the visitor started going inside SubQueryExpressions (it wasn't necessary before because we only needed to materialize top level collection).

[maumar]

@smitpatel ping