selftests: cgroup: Preserve command arguments in with_stress.sh

with_stress.sh invokes the requested command through unquoted $*. This
subjects the arguments to word splitting and pathname expansion:
arguments containing whitespace are split, empty arguments disappear,
and literal wildcard characters can expand to filenames.

Invoke the command through "$@" so that the command name and each
argument are passed as supplied by the caller.

Assisted-by: LLM
Signed-off-by: Ren Tamura <ren.tamura.oss@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

tools/testing/selftests/cgroup/with_stress.sh

@@ -87,7 +87,7 @@ time=0
 start=$(date +%s)
 
 while [ $time -lt $duration ] ; do
-	$*
+	"$@"
 	rc=$?
 	[ $rc -eq 0 ] || break
 	time=$(($(date +%s) - $start))