[VarDumper][VarExporter] Deal with DatePeriod->include_end_date on PHP 8.2

Author: nicolas-grekas

Tests/Fixtures/datetime.php

@@ -70,6 +70,7 @@
             'interval' => $o[6],
             'recurrences' => 5,
             'include_start_date' => true,
+            'include_end_date' => false,
         ],
     ]
 );