🐛 [BUG] 双轴图的 scale 计算问题

### 🐛 Bug description [Please make everyone to understand it]

柱形图可以完美计算比例


但是双轴图，总会少计算一个


### 💻 Link to minimal reproduction

Please provide a link by forking these links [g2plot](https://codesandbox.io/s/g2plot-reproduction-template-gyej1) or GitHub repo. What is a minimal reproduction, and why is it required?

### 📷 Step to reproduce

### 🏞 Expected result

双轴图可以计算出 1000

### 🚑 Any additional [like screenshots]

* **G2Plot Version**:
* **Platform**:

Start by reproducing the reported dual-axis chart case and tracing its scale calculation, comparing it with the bar-chart behavior described in the issue. Done means the dual-axis chart calculates the expected value of 1000 and the regression is covered by an appropriate test.

Written by the indexing model from the issue text.