fix(module:select): fix select dropdown position error

[vthinkxie]

close #3855

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Application (the showcase website) / infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: N/A

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[ ] No

Other information

[netlify]

Deploy preview for ng-zorro-master ready!

Built with commit a4521d9

https://deploy-preview-4267--ng-zorro-master.netlify.com

[netlify]

Deploy preview for ng-zorro-master ready!

Built with commit 1067179

https://deploy-preview-4267--ng-zorro-master.netlify.com

[codecov]

Codecov Report

Merging #4267 into master will decrease coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #4267      +/-   ##
==========================================
- Coverage   92.28%   92.27%   -0.01%     
==========================================
  Files         520      520              
  Lines       10978    10981       +3     
  Branches     1988     1988              
==========================================
+ Hits        10131    10133       +2     
  Misses        422      422              
- Partials      425      426       +1

Impacted Files	Coverage Δ
...mponents/select/nz-select-top-control.component.ts	100% <100%> (ø)	⬆️
components/select/nz-select.component.ts	96.29% <100%> (+0.02%)	⬆️
components/select/nz-select.service.ts	83.58% <100%> (+0.08%)	⬆️
components/time-picker/time-holder.ts	95.61% <0%> (-0.88%)	⬇️

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