Update arginfo for preg_match_all() to reflect reality.

Back when I implemented FR #53238 during the 5.4 development phase to make the
$matches parameter optional in preg_match_all(), it turns out I forgot to
update the arginfo to note that only 2 parameters are now required by
preg_match_all(). The function itself works fine, but reflection was reporting
the wrong number of required parameters.

ext/pcre/php_pcre.c

@@ -1866,7 +1866,7 @@ ZEND_BEGIN_ARG_INFO_EX(arginfo_preg_match, 0, 0, 2)
     ZEND_ARG_INFO(0, offset)
 ZEND_END_ARG_INFO()
 
-ZEND_BEGIN_ARG_INFO_EX(arginfo_preg_match_all, 0, 0, 3)
+ZEND_BEGIN_ARG_INFO_EX(arginfo_preg_match_all, 0, 0, 2)
     ZEND_ARG_INFO(0, pattern)
     ZEND_ARG_INFO(0, subject)
     ZEND_ARG_INFO(1, subpatterns) /* array */