Symfony version(s) affected: 4.2.*

Description
After updating the form component to version 4.2.3, the method ValidatorInterface::validate($formType) stopped returning any violations when it contains an invalid value object.

How to reproduce
This is the common code between the two versions
https://github.com/Loupax/broken_validation/blob/master/src/Controller/DefaultController.php
Please note how we don't actually submit the form. This is done on purpose.

You can switch between the following branches for a working an broken example
https://github.com/Loupax/broken_validation/blob/working_example/composer.json#L14
https://github.com/Loupax/broken_validation/blob/broken_example/composer.json#L14