ZTS: Avoid embedded blocks in bclone/bclone_prop_sync

If we write less than 113 bytes with enabled compression we get
embeded block, which then fails check for number of cloned blocks
in bclone_test.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Pawel Jakub Dawidek <pjd@FreeBSD.org>
Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes #16740