Symfony version(s) affected: 4.3.0-BETA2

Description
In symfony/framework-bundle@58e572e, protected static $client; was added to \Symfony\Bundle\FrameworkBundle\Test\WebTestCase.

I've upgraded my project to Symfony 4.3.0-BETA2 and had to fix my test suite and that of already multiple different libraries because it used $this->client to access the client (which is now triggering errors like Accessing static property Craue\FormFlowBundle\Tests\RevalidatePreviousStepsFlowTest::$client as non static, when it used to "work" before).

How to reproduce
Clone https://github.com/craue/CraueFormFlowBundle on branch "autoconfiguration" and run composer install && vendor/bin/phpunit.

Possible Solution
Either revert the addition, or write documentation as I think it's a BC break of sorts.