fsck_ffs: fix bad inode number errors

Fix fsck_ffs Pass 1b error exit "bad inode number 2 to nextinode".

(cherry picked from commit bc444e2ec6e6cc9d96d35ab7ce3c02c0da952fad)
(cherry picked from commit fab7c18ce3229d53b732fdfdbb6e9a1a1c72739a)

Fix fsck_ffs Pass 1b error exit "bad inode number 256 to nextinode".

(cherry picked from commit fe815b88b553667c40353c46b58f9779efa3570e)

PR: 255979
Sponsored by: Netflix

(cherry picked from commit e198c1dc8f6faaa85bd20990d15e3bcb9d081873)

Approved by: so
Errata: FreeBSD-EN-22:01.fsck_ffs