+CONSOLE WARNING: Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check http://xhr.spec.whatwg.org/.
Test that setRequestHeader properly checks for line feeds in header values.
%0AEvil%3A%20on -> SUCCESS, setRequestHeader() raised an exception SyntaxError: Failed to execute 'setRequestHeader' on 'XMLHttpRequest': ' Evil: on' is not a valid HTTP header field value.