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.
extern const int BAD_ARGUMENTS;
    extern const int DEADLOCK_AVOIDED;
    extern const int CLIENT_OUTPUT_FORMAT_SPECIFIED;
    extern const int UNKNOWN_PACKET_FROM_SERVER;
    extern const int NO_DATA_TO_INSERT;
    extern const int UNEXPECTED_PACKET_FROM_SERVER;
    extern const int INVALID_USAGE_OF_INPUT;
    extern const int CANNOT_SET_SIGNAL_HANDLER;
    extern const int UNRECOGNIZED_ARGUMENTS;
    extern const int LOGICAL_ERROR;
}
}
namespace ProfileEvents
{
    extern const Event UserTimeMicroseconds;
    extern const Event SystemTimeMicroseconds;
}
namespace DB
{
static ClientInfo::QueryKind parseQueryKind(const String & query_kind)
{
    if (query_kind == "initial_query")
        return ClientInfo::QueryKind::INITIAL_QUERY;
    if (query_kind == "secondary_query")
        return ClientInfo::QueryKind::SECONDARY_QUERY;
    if (query_kind == "no_query")
        return ClientInfo::QueryKind::NO_QUERY;
    throw Exception(ErrorCodes::BAD_ARGUMENTS, "Unknown query kind {}", query_kind);
}
static void incrementProfileEventsBlock(Block & dst, const Block & src)