CSS样式显示不正确

- [ ] I have searched the [issues](https://github.com/ant-design/ant-design/issues) of this repository and believe that this is not a duplicate.

### Reproduction link
[](https://codesandbox.io/s/antd-reproduction-template-forked-fl35m?file=/index.js)

### Steps to reproduce
1. 下载@ant-design/compatible 依赖包
2. 从包中导出Form, 写一个最简单的antd3的表单
3. 为表单项上 .ant-legacy-form-item-control-wrapper 当前元素添加 css: ` flex: 1 1 0%`
4.关于ant-legacy-form-item-control-wrapper 线上包括源码当中是默认有 flex: 1 1 0% 这个样式的，不知道为什么本地复现并没有这个样式，只能手动加上，线上是出现了问题

5.Input 表单项宽度丢失

### What is expected?
表单正常显示

### What is actually happening?
Input宽度丢失


| Environment | Info |
|---|---|
| antd | 4.12.2 |
| React | 16.8 |
| System | windows |
| Browser | chrome 88 |

Start with the linked CodeSandbox reproduction and its /index.js, then inspect how @ant-design/compatible supplies styles for .ant-legacy-form-item-control-wrapper. Confirm the missing flex: 1 1 0% rule and verify that the form renders normally with the Input width preserved.

Written by the indexing model from the issue text.