**Describe the bug**
`SYSTEM KILL` does not shutdown the server when run in a docker environment. I used https://hub.docker.com/r/yandex/clickhouse-server/ instructions to setup the docker.

**How to reproduce**
* ClickHouse server version 20.12.4 revision 54442.
```
myrotk@altinity-qa-cosmic3:~$ docker pull yandex/clickhouse-server
Using default tag: latest
latest: Pulling from yandex/clickhouse-server
da7391352a9b: Pull complete
14428a6d4bcd: Pull complete
2c2d948710f2: Pull complete
076cd2c6a81e: Pull complete
201ea6cda8c8: Pull complete
0d7b4e598027: Pull complete
0d86a58e3639: Pull complete
3b78a4fd0f92: Pull complete
86d65487f611: Pull complete
dc82dea7d6fe: Pull complete
Digest: sha256:8f669dafd35eb527210cc77973ed927734dff2c2cafd345823c8c99769124fd1
Status: Downloaded newer image for yandex/clickhouse-server:latest
docker.io/yandex/clickhouse-server:latest

myrotk@altinity-qa-cosmic3:~$ docker run -d --name some-clickhouse-server --ulimit nofile=262144:262144 yandex/clickhouse-server
35603911ec6c5737f069a019a60d03270cefe78e52c77d1bc6ff33a0548ae97e

myrotk@altinity-qa-cosmic3:~$ docker run -it --rm --link some-clickhouse-server:clickhouse-server yandex/clickhouse-client --host clickhouse-server
Unable to find image 'yandex/clickhouse-client:latest' locally
latest: Pulling from yandex/clickhouse-client
f22ccc0b8772: Pull complete
3cf8fb62ba5f: Pull complete
e80c964ece6a: Pull complete
6f064a173914: Pull complete
37a06aaf9ee5: Pull complete
Digest: sha256:504e18bed5162a20bbff6071ca1b7c7baca1380d2e2755e4d6bf4bac7e534531
Status: Downloaded newer image for yandex/clickhouse-client:latest
ClickHouse client version 20.12.4.5 (official build).
Connecting to clickhouse-server:9000 as user default.
Connected to ClickHouse server version 20.12.4 revision 54442.

35603911ec6c :) SYSTEM KILL

SYSTEM KILL

Query id: 0da8cfef-36c8-4de9-8c12-3e9175c5aed0

Ok.

0 rows in set. Elapsed: 0.002 sec.

35603911ec6c :)



logger().warning("Cannot do prctl to ask termination with parent.");
#endif
            return;
        }
        
        setThreadName("clckhouse-watch");   
        if (argv0)
        {
            const char * new_process_name = "clickhouse-watchdog";
            memset(argv0, 0, original_process_name.size());
            memcpy(argv0, new_process_name, std::min(strlen(new_process_name), original_process_name.size()));
        }
        logger().information(fmt::format("Will watch for the process with pid {}", pid));
        
        addSignalHandler(
            {SIGHUP, SIGUSR1, SIGINT, SIGQUIT, SIGTERM},
            [](int sig, siginfo_t *, void *)
            {
                
                
                if (sig == SIGINT)
                    return;
                const char * error_message = "Cannot forward signal to the child process.\n";
                if (0 != ::kill(pid, sig))
                {
                    auto res = write(STDERR_FILENO, error_message, strlen(error_message));
                    (void)res;
                }
            },
            nullptr);