Fixed testHelpTextWithCustomBanner() failing with "php phpunit.php -c phpunit.xml"

Sorry, Getopt.php and git newbie here (that's why there are three commits for what should've been only one).

I ran the Getopt.php tests via "php phpunit.php -c phpunit.xml". testHelpTextWithCustomBanner() failed with "UnexpectedValueException: Option c is unknown".

I think parse('') helps because then the test doesn't pick up the arguments I'm passing to the PHPUnit command-line test runner?