Test integer credit cards only on 64 bits system

Integer credit card fails on 32bits system because the integer is too long.

Method for 64bits detection: http://stackoverflow.com/a/5424121/1731473

tests/IsoCodes/Tests/CreditCardTest.php

@@ -26,10 +26,24 @@ public function getValidValues()
             array('4903010000000009'),  //Switch
             array('4111111111111111'),  //Visa
             array('6304100000000008'),  //Laser
-            array(6304100000000008),    //Laser
         );
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function getLegacyValidValues()
+    {
+        $values = [];
+
+        // To be removed on 4.0.
+        if (8 === PHP_INT_SIZE) { // This test will success only on 64bits systems.
+            $values[] = [6304100000000008]; // Laser
+        }
+
+        return $values;
+    }
+
     /**
      * {@inheritdoc}
      */