Merge pull request #47140 from cyx1231st/wip-seastore-split-fix

crimson/os/seastore: do not assign gen/hint when split a clean extent

Reviewed-by: Samuel Just <sjust@redhat.com>
Reviewed-by: Zhang Song <zhangsong325@gmail.com>

diff --cc src/crimson/os/seastore/transaction_manager.h
Simple merge