select选择器多选的情况下，下拉列表和select输入框距离没有贴在一起

[lait233]

Reproduction link

https://stackblitz.com/edit/angular-jwy6t4-xhin52

Steps to reproduce

鼠标依次选择 a10 b11 c12 d13。然后用鼠标或者回车键在下拉选项列表里取消选择a10。 select框就会和下拉框出现一段空白距离,

What is expected?

下拉列表应该和select输入框紧贴在一起

What is actually happening?

下拉列表和select输入框出现了分开距离

Environment	Info
ng-zorro-antd	8.1.0
Browser	chrome74

[zorro-bot]

Translation of this issue:

In the case of multiple selection of the select selector, the drop-down list and the select input box are not attached together.

Reproduction link

https://stackblitz.com/edit/angular-jwy6t4-xhin52

Steps to reproduce

Mouse then select a10 b11 c12 d13. Then use the mouse or the Enter key to deselect a10 in the drop-down list of options. The select box will appear a blank distance from the drop-down box.

What is expected?

The drop-down list should be tied to the select input box

What is actually happening?

The drop-down list and the select input box appear separated

Environment	Info
ng-zorro-antd	8.1.0
Browser	chrome74

[vnobo]

点击X的时候吧。。。这是响应事件的样式问题