encryption: fix offset inconsistency between crypter and file (#15092) (

#15205)

close #15080

Fix offset inconsistency between crypter and file that could cause data corruption when file I/O is interrupted.

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>
Signed-off-by: Xinye Tao <xy.tao@outlook.com>

Co-authored-by: Xinye Tao <xy.tao@outlook.com>