Add SKIPIF to test requiring mbregex

Author: nikic

ext/mbstring/tests/mb_ereg_search_invalid_pattern.phpt

@@ -1,5 +1,7 @@
 --TEST--
 mb_ereg_search() with invalid pattern should discard old matches
+--SKIPIF--
+<?php if (!function_exists("mb_ereg")) print "skip requires mbregex"; ?>
 --FILE--
 <?php