Fix infinite loop for CSV with all lines empty

Only occured with multiline CSV files

tests/bootstrap.php

@@ -3,3 +3,6 @@ require_once(dirname(__DIR__) . '/vendor/autoload.php');
 
 require_once(dirname(__DIR__) . '/tests/Spout/TestUsingResource.php');
 require_once(dirname(__DIR__) . '/tests/Spout/ReflectionHelper.php');
+
+// Make sure a timezone is set to be able to work with dates
+date_default_timezone_set('UTC');