MDL-44871 Atto clear: Fix behat errors with phantomjs
MDL-44871 Atto align: Fix behat test in phantomjs
MDL-44871 Atto: Add @_bug_phantomjs to some Atto tests

I am seeing some wierd with some of the Atto buttons - but it only happens on phantomjs (not firefox/chrome).
MDL-44871 Atto: Make the behat tests work with chromedriver