repair: helper to import on-disk inobt records to in-core trees

repair: helper to import on-disk inobt records to in-core trees

In the common case, the in-core inode state from the on-disk inobt
records is imported from the inobt and validated against the finobt (if
one exists). When both trees exist along with some form of corruption,
it's possible to find inodes in the finobt not tracked by the inobt.
While this is unexpected, we attempt to repair by importing the inodes
from the finobt.

The associated code in the finobt scan function mirrors the associated
code in the inobt scan function. Factor this into a separate helper that
can be called by either tree scan.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>