Query: correlated collection optimization doesn't get applied for subqueries with AsQueryable

[maumar]

Currently we only apply correlated collection optimization of the subquery doesn't have any result operators. We should allow AsQueryable, for cases like this:

var query = ctx.LevelOne.Select(l1 => new 
{ 
    l1.Id, 
    Collection = l1.OneToMany_Optional.AsQueryable().Include(l2 => l2.OneToOne_Required_FK).ToList() 
});

i.e. to apply include on a collection when the source qsre is not projected directly (#12181 has more details)

[maumar]

need to decide how we approach Include for those complex scenarios.

[ajcvickers]

@smitpatel to link to Include issue.

[smitpatel]

Based on include path interpretation we can determine if we need this kind of pattern supported. #12737

[ajcvickers]

Moving this to 3.0 to consider as part of the overall 3.0 query plan: #12795