Update expected output for sysviews test because of changed default value of enable_seqscan_prefetch

Author: knizhnik

src/test/regress/expected/sysviews.out

@@ -129,7 +129,7 @@ select name, setting from pg_settings where name like 'enable%';
  enable_partitionwise_aggregate | off
  enable_partitionwise_join      | off
  enable_seqscan                 | on
- enable_seqscan_prefetch        | on
+ enable_seqscan_prefetch        | off
  enable_sort                    | on
  enable_tidscan                 | on
 (21 rows)