myChart.setOption({}) 时 lines.data 丢失
### Version
4.8.0

### Steps to reproduce
myChart.setOption({}) 时, lines类型的线数据会丢失, 其他类型的数据(如line)依然存在.
这个方法的行为是不是应该统一?

https://gallery.echartsjs.com/editor.html?c=xeqTwJtMgx&v=1

- before:
![image](assets/apache__echarts-12850/001.png)

- after:
![image](assets/apache__echarts-12850/002.png)

### What is expected?

myChart.setOption({}) 要么数据全丢, 要么全保留

### What is actually happening?
lines类型的线数据丢失

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## Relevant pre-fix discussion

### Issue #12836

#### Comment at 2020-06-22T14:58:12Z

@myshzzx 
代码，在本地运行，如图所示，可以显示lines类型的线数据
![image](assets/apache__echarts-12850/003.png)
![image](assets/apache__echarts-12850/004.png)