[release/8.0] Visit inside InlineQueryRootExpression in nav expansion

[roji]

Fixes #32331, backports #32460.

Description

As part of the primitive collection work for EF 8, the new InlineCollectionQueryRoot expression type was introduced to represent collections which are inline in the LINQ query (e.g. Where(b => new[] { 1, 3 }.Where(...)). However, our navigation expansion visitor, which is responsible for processing navigations, was not modified to visit inside this new expression type; as a result, navigations inside subqueries within InlineCollectionQueryRoot do not work.

Customer impact

Queries which include navigations inside an inline collection fail to execute, e.g.:

_ = context.Blogs
    .Select(b => new[] { b.Updated, b.Posts.Max(p => p.Updated) }.Max())
    .ToList();

Such queries used to work in 7.0, if the code in question was in the top-level Select (and got client-evaluated).

How found

Customers reported on 8.0

Regression

Yes

Testing

Added.

Risk

Low - very targeted and single, simple fix (but in the query pipeline, which is never zero-risk). Quirk added.

[AndriySvyryd]

Note that the branch is currently closed.

[wtgodbe]

@roji can you resolve the merge conflicts? Then I can merge