Entity equality: handle non-anonymous types in projection

[roji]

We currently handle projecting through anonymous types, but not non-anonymous types. We should visit the MemberInitExpression and perform entity equality rewriting.

Examples:

[ConditionalTheory]
[MemberData(nameof(IsAsyncData))]
public virtual Task Entity_equality_through_DTO_projection(bool isAsync)
    => AssertQuery<Order>(
        isAsync,
        o => o
            .Select(o => new OrderDTO { Customer = o.Customer })
            .Where(x => x.Customer != null),
        entryCount: 89);

private class OrderDTO
{
    public Customer Customer { get; set; }
}

Raised in #16719, thanks @smitpatel for first analysis.

[fschlaef]

Confirmed working with 3.0.0-rc1 👍

[roji]

Thanks for the confirmation!