CPU usage is misreported.

Currently "0 CPU" means "no CPU metric received in the previous ProfileEvents packet". But there can be many ProfileEvents packets and only a few with CPU increment.

That's why the CPU metric shows something weird like:
```
0
0
0
0
0
1234
0
0
0
...
```

This is unbearable, and the CPU metric should be either fixed or removed altogether.
{
    if (!logs_out_stream)
    {
        WriteBuffer * wb = out_logs_buf.get();
        bool color_logs = false;
        if (!out_logs_buf)
        {
            if (server_logs_file.empty())
            {
                /// Use stderr by default
                :make_unique<WriteBufferFromFileDescriptor>(STDERR_FILENO);
                wb = out_logs_buf.get();
                color_logs = stderr_is_a_tty;
            }
            else if (server_logs_file == "-")
            {
                /// Use stdout if --server_logs_file=- specified
                wb = &std_out;
                color_logs = stdout_is_a_tty;
            }
            else
            {
                out_logs_buf
                    = std::make_unique<WriteBufferFromFile>(server_logs_file, DBMS_DEFAULT_BUFFER_SIZE, O_WRONLY | O_APPEND | O_CREAT);
                wb = out_logs_buf.get();