selftests/damon/sysfs_memcg_path_leak.sh: use kmemleak

selftests/damon/sysfs_memcg_path_leak.sh: use kmemleak

Patch series "selftests/damon: improve leak detection and wss estimation
reliability".

Two DAMON selftets, namely 'sysfs_memcg_leak' and
'sysfs_update_schemes_tried_regions_wss_estimation' frequently show
intermittent failures due to their unreliable leak detection and working
set size estimation.  Make those more reliable.

This patch (of 5):

sysfs_memcg_path_leak.sh determines if the memory leak has happened by
seeing if Slab size on /proc/meminfo increases more than expected after an
action.  Depending on the system and background workloads, the reasonable
expectation varies.  For the reason, the test frequently shows
intermittent failures.  Use kmemleak, which is much more reliable and
correct, instead.

Link: https://lkml.kernel.org/r/20260117020731.226785-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20260117020731.226785-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>