jbd2: move escape handle to futher improve jbd2_journal_write_metadata_buffer

Move escape handle to futher improve code readability and remove some
repeat check.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20240801013815.2393869-7-shikemeng@huaweicloud.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>