Fix test title and limit it to ICU >= 4.8

Author: cataphract

ext/intl/tests/resourcebundle_null_mandatory_args.phpt

@@ -1,11 +1,13 @@
 --TEST--
-IntlCalendar::setTime() basic test
+ResourceBundle constructor bundle accepts NULL for first two arguments
 --INI--
 date.timezone=Atlantic/Azores
 --SKIPIF--
 <?php
 if (!extension_loaded('intl'))
 	die('skip intl extension not enabled');
+if (version_compare(INTL_ICU_VERSION, '4.8') < 0)
+	die('skip ICU >= 4.8 only');
 --FILE--
 <?php
 ini_set("intl.error_level", E_WARNING);