Avoid unnecessary string refcounting in ext/date (php#17890)

Author: nielsdos

ext/date/php_date.c

@@ -4682,9 +4682,10 @@ static void php_date_interval_initialize_from_hash(zval **return_value, php_inte
 		if (z_arg && Z_TYPE_P(z_arg) == IS_FALSE) { \
 			(*intobj)->diff->member = TIMELIB_UNSET; \
 		} else if (z_arg && Z_TYPE_P(z_arg) <= IS_STRING) { \
-			zend_string *str = zval_get_string(z_arg); \
+			zend_string *tmp_str; \
+			zend_string *str = zval_get_tmp_string(z_arg, &tmp_str); \
 			DATE_A64I((*intobj)->diff->member, ZSTR_VAL(str)); \
-			zend_string_release(str); \
+			zend_tmp_string_release(tmp_str); \
 		} else { \
 			(*intobj)->diff->member = -1LL; \
 		} \