TestInspectOomKilledTrue: skip on cgroup v2

The test fails intermittently on cgroup v2.

```
=== FAIL: amd64.integration.container TestInspectOomKilledTrue (0.53s)
    kill_test.go:171: assertion failed: true (true bool) != false (inspect.State.OOMKilled bool)
```

Tracked in issue 41929

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

integration/container/kill_test.go

@@ -155,6 +155,7 @@ func TestInspectOomKilledTrue(t *testing.T) {
 	skip.If(t, testEnv.DaemonInfo.OSType == "windows")
 	skip.If(t, testEnv.DaemonInfo.CgroupDriver == "none")
 	skip.If(t, !testEnv.DaemonInfo.MemoryLimit || !testEnv.DaemonInfo.SwapLimit)
+	skip.If(t, testEnv.DaemonInfo.CgroupVersion == "2", "FIXME: flaky on cgroup v2 (https://github.com/moby/moby/issues/41929)")
 
 	defer setupTest(t)()
 	ctx := context.Background()