tests/int: fix update cpu.idle failure on CS9

Systemd v252 (available in CentOS Stream 9 in our CI) added support
for setting cpu.idle (see [1]). The way it works is:
 - if CPUWeight == 0, cpu.idle is set to 1;
 - if CPUWeight != 0, cpu.idle is set to 0.

This behavior breaks the existing test case, as described in [2].

To fix, skip the last check in the test case in case a newer systemd
is used.

Fixes: opencontainers#3786

[1] systemd/systemd#23299
[2] opencontainers#3786

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

tests/integration/update.bats

@@ -454,6 +454,8 @@ EOF
 		check_cgroup_value "cpu.idle" "$val"
 	done
 
+	# https://github.com/opencontainers/runc/issues/3786
+	[ "$(systemd_version)" -ge 252 ] && return
 	# test update other option won't impact on cpu.idle
 	runc update --cpu-period 10000 test_update
 	[ "$status" -eq 0 ]