DatePicker 弹框位置错误

[YaoKaiPeng]

• I have searched the issues of this repository and believe that this is not a duplicate.

Reproduction link

Steps to reproduce

点击选择日期，发现日期确定按钮超出屏幕，滚动页面，触发Affix效果，日期选择框依然被挡

What is expected?

日期选择框可以根据屏幕显示位置来自动呈现位置

What is actually happening?

目前的日期选择框是根据页面高度来处理位置的，当页面底部有滚动条时，日期框会一直是从下方弹出。

Environment	Info
antd	4.16.0
React	17.0.2
System	win10
Browser	chrome

[afc163]

Fixed in antd 5.x: https://codesandbox.io/s/vigilant-pine-lbbifx?file=/package.json