使用dataset时， 系列名为纯数字时出现报错echarts 配置项内容和展示

使用echart版本： 4.2.0 Chrome版本： 74.0（32位） 相信与版本无关。 当数据为如下样子时， 会报下面的错误： ``` dataset: { source: [ ["value","8","9","10","11","12", '13', '14', '15', '16', '17', '18'], [0.057,0,0,0,0,0,0,0,0,0,0,0], [0.076,2,11,12,25,40,49,38,42,61,62,37], [0.095,0,1,1,3,8,5,7,9,11,8,7], [0.114,0,1,3,2,3,5,6,7,9,8,5], ] } ``` 报错信息： TypeError: Cannot read property 'width' of undefined 查看源代码，报错位置如下： ``` // In case width or height are too small. function getLineWidth(itemModel, rawLayout) { var lineWidth = itemModel.get(BAR_BORDER_WIDTH_QUERY) || 0; return Math.min(lineWidth, Math.abs(rawLayout.width), Math.abs(rawLayout.height)); } ``` 报错情况： 当数据系列小于等于5时，显示没有问题，大于5个就会出现上面的报错。系列大于五个时，系列名必须为字母开头的字符串才不会报错。 此问题也有其他人提交过，希望echarts开发团队尽快修复bug。 希望尽快得到得到官方的解释或者修复bug，谢谢。

      option = {
    tooltip : {
        trigger: 'axis',
        axisPointer : {            // 坐标轴指示器，坐标轴触发有效
            type : 'shadow'        // 默认为直线，可选为：'line' | 'shadow'
        }
    },
    dataset: {
        source: [
            ["value","8","9","10","11","12", '13', '14', '15', '16', '17', '18'], // 将这一条的数字字符串前加个字母就不报错了
            [0.057,0,0,0,0,0,0,0,0,0,0,0],
            [0.076,2,11,12,25,40,49,38,42,61,62,37],
            [0.095,0,1,1,3,8,5,7,9,11,8,7],
            [0.114,0,1,3,2,3,5,6,7,9,8,5],
            [0.133,0,0,0,1,3,4,7,7,4,3,5],
            [0.152,0,0,1,1,2,3,3,5,5,6,2],
            [0.171,0,0,0,2,1,2,4,8,2,4,1],
            [0.19,1,1,0,0,1,2,1,5,7,2,4],
            [0.209,1,0,0,0,1,4,2,3,2,4,0],
            [0.228,0,0,2,0,1,0,1,3,4,0,2],
            [0.247,0,0,0,0,1,0,0,2,3,0,1],
            [0.266,1,0,0,0,0,0,1,2,0,2,6],
            [0.285,0,0,1,1,1,0,2,3,0,1,2],
            [0.304,0,0,0,0,0,0,1,1,3,2,1],
            [0.323,0,0,0,0,0,0,0,3,1,1,0],
            [0.342,0,0,0,0,0,0,2,3,0,1,0],
            [0.361,0,0,1,0,0,0,0,0,2,0,0],
            [0.38,0,0,0,0,0,0,0,0,1,1,1],
            [0.399,0,0,0,0,0,1,0,2,2,0,2],
            [0.418,0,0,0,0,0,0,0,0,0,0,1],
            [0.437,0,0,0,1,1,0,0,1,2,0,0],
            [0.456,0,0,0,0,1,0,0,1,1,0,0],
            [0.475,0,0,0,0,0,0,0,0,2,0,0],
            [0.494,0,0,0,0,0,1,0,1,0,0,0],
            [0.513,0,1,0,0,0,0,0,0,0,2,0],
            [0.532,0,0,0,0,1,1,0,0,1,0,0],
            [0.551,0,0,1,0,0,0,0,0,1,1,0],
            [0.57,0,0,0,0,0,0,0,0,1,0,1],
            [0.589,0,0,0,0,0,0,0,0,1,0,0],
            [0.608,0,0,0,0,0,0,0,0,1,0,0],
            [0.627,0,0,0,0,0,0,1,0,0,0,0],
            [0.665,0,0,0,0,0,2,0,0,0,0,0],
            [0.684,0,0,0,0,0,0,0,0,0,0,1],
            [0.703,0,0,1,0,1,0,0,0,0,1,0],
            [0.722,0,0,0,0,0,1,0,0,1,0,0],
            [0.741,0,0,1,0,0,0,1,0,1,0,0],
            [0.76,0,1,0,0,0,0,0,0,1,0,0],
            [0.779,0,0,0,0,0,1,0,0,0,0,0],
            [0.836,0,0,0,0,1,0,0,0,0,0,0],
            [0.893,0,0,0,0,0,0,0,0,0,0,1],
            [0.95,0,1,0,0,0,0,0,0,0,0,0],
            [0.969,0,0,0,0,0,0,0,0,1,0,0],
            [0.988,0,0,0,0,0,0,0,0,0,0,1],
            [1.007,0,0,0,0,0,1,0,0,0,2,0],
            [1.045,0,0,0,0,0,0,0,0,1,0,0],
            [1.064,0,0,0,0,0,1,0,0,0,0,0],
            [1.102,0,0,0,0,0,0,0,0,0,0,1],
            [1.121,0,0,0,0,0,1,0,0,0,0,0],
            [1.197,0,0,0,0,0,0,1,0,0,0,0],
            [1.235,0,0,0,1,0,0,0,0,0,0,0],
            [1.254,0,0,0,0,1,0,0,0,0,0,0],
            [1.52,0,0,1,0,0,0,0,0,0,0,0],
            [1.558,0,0,0,0,0,1,0,0,0,0,0],
            [1.672,0,0,0,0,0,0,1,0,0,0,0],
            [1.729,0,0,0,0,0,0,0,0,0,1,0],
            [1.767,0,0,0,0,1,0,0,0,0,0,0],
            [1.919,0,0,1,0,0,0,0,0,0,0,0],
            [1.995,0,0,0,1,0,0,0,0,0,0,0],
            [2.071,0,0,0,0,1,0,0,0,0,0,0],
            [2.299,0,0,0,0,0,0,0,0,1,0,0],
            [2.622,0,0,0,0,0,0,0,0,0,1,0],
            [3.154,0,0,0,0,0,1,0,1,0,0,0],
            [3.496,0,0,0,0,1,1,0,0,1,0,0]
        ]
    },
    legend: {
        type: 'scroll'
    },
    grid: {
        left: '3%',
        right: '4%',
        bottom: '3%',
        containLabel: true
    },
    xAxis : [
        {
            type : 'category'
        }
    ],
    yAxis : [
        {
            type : 'value'
        }
    ],
    series : Array(11).fill({
        animation:false,
        stack:1,
        type:"bar"
    })
};