JsonData-testextensions now non voting

The JsonData unit tests do not work for now. MediaWiki phpunit.php
wrapper can not find any tests since they are not registered. So just
ignore the result of the testing job for now.

See also https://gerrit.wikimedia.org/r/#/c/52292/

Change-Id: I76a6a8814587bd4679d41c4c43da1bdafd836ef3