[WIP] Do not expose routing 404 exception for protected route

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes (did fail locally though...)
| Fixed tickets | #2679
| License       | MIT
| Doc PR        | not related

I'm not sure if this is seen as a new feature or as a bug fix, so I just
submitted it to the master branch.
Symfony code usually checks if the OS is Windows using this snippet:

```php
if (defined('PHP_WINDOWS_VERSION_BUILD')) {
    // ...
}
```