Missing argument for PHPUnit_TextUI_TestRunner::run

[SanderKnape]

This closed issue mentions two different warning messages. The issue is closed but looking at the doRun function and its callee in the same class, there appears to be a missing argument there which causes the aformentioned PHP warnings. In my experience, both CircleCI and Codeship execute the tests through that callee and I see the warning messages. Locally though on my laptop, the doRun function is executed from the Command.php file, where the $exit parameter is provided and I therefore don't see any warnings.

Looks to me either the erroneous calling function needs to be changed, or the $exit parameter should be given a default. I don't know which is more appropriate. I can make a PR if someone enlightens me with the proper solution :)