Disable route normalizer on remote image style routes to avoid problems with redirect module

Today I've spent a lot of time on debugging and investigating the following problem:

I'm using remote_stream_wrapper in a client project to attach images during a migrate import. This works fine and the images are showing up, as they should - at least if you render them without image style.

As soon as I tried to render them via image style, I got access denied errors. On further investigation, I found out that there's actually a redirect happening, resulting in the second request not having the import "file" query attribute set.

Finally I found out, that the presence of the redirect module caused the problem.

The solution is finally very trivial: the image style routes must have set '_disable_route_normalizer' to TRUE in order to prevent that redirect's route normalizer is causing a redirect. Redirect itself is altering the core 'image.style_public' and 'system.files' routes in its \Drupal\redirect\Routing\RouteSubscriber class.

The remaining question is, which of the two modules should do this integration work. Even if in a default setup without redirect module, the presence of '_disable_route_normalizer' is unimportant (but also does no harm), I was tending to say, remote_stream_wrapper should take care of this.

I've contacted the maintainers of both modules, @davereid and @berdir on Twitter. berdir mentionend a pending core patch, that the route normalizer is based upon and so proposed the same: "The route normalizer is based on a core patch that will eventually get in, so I think other contrib modules should add it themselves" (https://twitter.com/berdir/status/861930414117707780)

So I'll propose a patch here...