selftests/damon/sysfs: test tried_regions/total_bytes file

Update sysfs.sh DAMON selftest for checking existence of 'total_bytes'
file under the 'tried_regions' directory of DAMON sysfs interface.

Link: https://lkml.kernel.org/r/20230802213222.109841-4-sj@kernel.org


Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>