a-select 下拉框，操作鼠标滚轮上下滚，偶现滚不动 #3483
Description
- I have searched the issues of this repository and believe that this is not a duplicate.
Version
1.7.2
Environment
Chrome 版本 87.0.4280.88（正式版本） (x86_64)
Reproduction link
Steps to reproduce
打开复现sandbox链接，右侧运行界面，激活下拉框，使用鼠标滚轮快速无序滚动下拉框，当下拉条在顶部或者底部时，偶现滚不动且无法触发popupScroll
What is expected?
操作鼠标滚轮滚动，不会偶现滚不动的现象。
What is actually happening?
a-select 下拉框，操作鼠标滚轮上下滚，滚到顶部或底部时，偶现滚不动并且不触发popupScroll的情况。demo在此 https://codesandbox.io/s/vue-template-forked-sdju1?file=/src/App.vue