fix(module:cascader,checkbox,switch,tooltip): fix memory leak problem

[binglingshuang]

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?

[x] 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?

Fix memory leak problem.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

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[codecov]

Codecov Report

Merging #3416 into master will decrease coverage by 1.16%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #3416      +/-   ##
==========================================
- Coverage   96.66%   95.49%   -1.17%     
==========================================
  Files         609      609              
  Lines       13187    13205      +18     
  Branches     1803     1803              
==========================================
- Hits        12747    12610     -137     
- Misses        199      215      +16     
- Partials      241      380     +139

Impacted Files	Coverage Δ
components/cascader/nz-cascader.component.ts	96.19% <100%> (-1.26%)	⬇️
components/tooltip/nz-tooltip.directive.ts	97.11% <100%> (-1.8%)	⬇️
components/checkbox/nz-checkbox-group.component.ts	100% <100%> (ø)	⬆️
components/switch/nz-switch.component.ts	98.27% <100%> (-1.73%)	⬇️
components/core/util/getMentions.ts	50% <0%> (-16.67%)	⬇️
components/core/scroll/nz-scroll.service.ts	66.03% <0%> (-13.21%)	⬇️
components/core/polyfill/request-animation.ts	20% <0%> (-12%)	⬇️
components/slider/nz-slider-step.component.ts	88.88% <0%> (-11.12%)	⬇️
components/i18n/nz-i18n.service.ts	80.95% <0%> (-9.53%)	⬇️
components/core/util/textarea-caret-position.ts	42.1% <0%> (-8.78%)	⬇️
... and 58 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b0f353c...5a1b2e7. Read the comment docs.

[codecov]

Codecov Report

Merging #3416 into master will decrease coverage by 1.16%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #3416      +/-   ##
==========================================
- Coverage   96.66%   95.49%   -1.17%     
==========================================
  Files         609      609              
  Lines       13187    13205      +18     
  Branches     1803     1803              
==========================================
- Hits        12747    12610     -137     
- Misses        199      215      +16     
- Partials      241      380     +139

Impacted Files	Coverage Δ
components/cascader/nz-cascader.component.ts	96.19% <100%> (-1.26%)	⬇️
components/tooltip/nz-tooltip.directive.ts	97.11% <100%> (-1.8%)	⬇️
components/checkbox/nz-checkbox-group.component.ts	100% <100%> (ø)	⬆️
components/switch/nz-switch.component.ts	98.27% <100%> (-1.73%)	⬇️
components/core/util/getMentions.ts	50% <0%> (-16.67%)	⬇️
components/core/scroll/nz-scroll.service.ts	66.03% <0%> (-13.21%)	⬇️
components/core/polyfill/request-animation.ts	20% <0%> (-12%)	⬇️
components/slider/nz-slider-step.component.ts	88.88% <0%> (-11.12%)	⬇️
components/i18n/nz-i18n.service.ts	80.95% <0%> (-9.53%)	⬇️
components/core/util/textarea-caret-position.ts	42.1% <0%> (-8.78%)	⬇️
... and 58 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b0f353c...440dfc6. Read the comment docs.