Filtered child entities in projection are not tracked

[havotto]

When child entities are filtered in a projection, these child entities are not tracked, but added to the parent's navigation collection. Also, the inverse navigation properties are not fixed up.

This issue is quite related to issue 7131

Steps to reproduce

Here is the repo with tests for details: Repo

Further technical details

EF Core version: 2.0.0
Database Provider: Microsoft.EntityFrameworkCore.Sqlite
Operating system: Win 10
IDE: Visual Studio 2017

[ajcvickers]

Note for triage:
In this case, Child entities are tracked:

var result = ctx.Parents.Select(p =>
new
{
    Parent = p,
    Children = p.Children
})
.First();

In this case, Child entities are not tracked:

var result = ctx.Parents.Select(p =>
new
{
    Parent = p,
    Children = p.Children.Where(c => c.Name.Length > 0).ToList()
})
.First();

[anpete]

Similar to #7569. @maumar is there a dupe of this?

[maumar]

fixed in b95f23f