Add a command that will freeze clickhouse-server process with STOP signal and wakeup it after specified amount of time.
This is needed for testing (fault injection).

Wakeup can be done with `ShellCommand` running `sleep N && kill -CONT pid`
parseDatabaseAndTableName(pos, expected, res->database, res->table);
                }
                else if (ParserKeyword{"ZKPATH"}.ignore(pos, expected))
                {
                    ASTPtr path_ast;
                    if (!ParserStringLiteral{}.parse(pos, path_ast, expected))
                        return false;
                    String zk_path = path_ast->as<ASTLiteral &>().value.safeGet<String>();
                    if (!zk_path.empty() && zk_path[zk_path.size() - 1] == '/')
                        zk_path.pop_back();
                    res->replica_zk_path = zk_path;
                }
                else
                    return false;
            }
            else
                res->is_drop_whole_replica = true;
            break;
        }
        case Type::RESTART_REPLICA:
        case Type::SYNC_REPLICA:
            if (!parseDatabaseAndTableName(pos, expected, res->database, res->table))
                return false;
            break;
        case Type::STOP_DISTRIBUTED_SENDS:
        case Type::START_DISTRIBUTED_SENDS:
        case Type::FLUSH_DISTRIBUTED:
        {
            String cluster_str;
            if (ParserKeyword{"ON"}.ignore(pos, expected))