use DateTime::getTimestamp() as argument to IntlDateFormatter::format() for PHP installation consistency
Test Day Select Element is populated with 31 value options to test protected method Zend\Form\View\Helper\FormDateSelect::getDaysOptions()
Test Month Select Element is populated with 12 value options to test protected method Zend\Form\View\Helper\FormDateSelect::getMonthsOptions()
Merge remote-tracking branch 'upstream/master'
Merge branch 'hotfix/4687'

Close #4687