Symfony version(s) affected: all ?

Description
phpunit-bridge ignores the value "disabled" for the environment variable SYMFONY_DEPRECATIONS_HELPER when set in phpunit.xml. The value "weak" works as expected.
Also, setting this environment variable in the shell works as expected.

Tested with phpunit-bridge-4.1.4

How to reproduce
set in phpunit.xml

<php>
  <env name="SYMFONY_DEPRECATIONS_HELPER" value="disabled" />
</php>

and run a test which will cause a deprecation warning.