Revert "XFAIL payload_test.phpt when run with ASan"

This reverts commit 2b9f420.

Author: cmb69

ext/pdo_firebird/tests/payload_test.phpt

@@ -4,7 +4,6 @@ FB payload server satisfies connection attempt
 <?php
 if (!extension_loaded('pdo_firebird')) die("skip pdo_firebird extension not available");
 if (!extension_loaded('sockets')) die("skip sockets extension not available");
-if (getenv('SKIP_ASAN')) die('xfail leaks memory FIXME');
 ?>
 --FILE--
 <?php