time scale label should in local time when timestamp (in UTC) input, tick should align with day.
        
        time scale label should in UTC time when option.useUTC is `true`, tick should not align with day.
        
        useUTC: null, should display '00:00 01-03' in tooltip on the 1st point
        
        useUTC: true, should display '16:00 01-02' in tooltip on the 1st point