test: add RouterTestingModule to spec files

[simplejason]

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

[zorro-bot]

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[codecov]

Codecov Report

Merging #7605 (7ee6a52) into master (8b92c63) will increase coverage by 1.64%.
The diff coverage is n/a.

❗ Current head 7ee6a52 differs from pull request most recent head 81b7a2a. Consider uploading reports for the commit 81b7a2a to get more accurate results

@@            Coverage Diff             @@
##           master    #7605      +/-   ##
==========================================
+ Coverage   90.43%   92.08%   +1.64%     
==========================================
  Files         502      502              
  Lines       16752    16752              
  Branches     2629     2629              
==========================================
+ Hits        15150    15426     +276     
+ Misses       1314     1057     -257     
+ Partials      288      269      -19     

Impacted Files	Coverage Δ
components/table/src/cell/th-addon.component.ts	90.12% <0.00%> (+2.46%)	⬆️
components/dropdown/dropdown-menu.component.ts	88.23% <0.00%> (+5.88%)	⬆️
components/tabs/tabset.component.ts	92.89% <0.00%> (+12.18%)	⬆️
components/menu/menu-group.component.ts	78.57% <0.00%> (+14.28%)	⬆️
components/tabs/tab-nav-operation.component.ts	68.75% <0.00%> (+15.62%)	⬆️
components/tabs/tabs-ink-bar.directive.ts	87.09% <0.00%> (+16.12%)	⬆️
components/menu/menu-item.directive.ts	76.38% <0.00%> (+19.44%)	⬆️
components/menu/menu.directive.ts	93.93% <0.00%> (+19.69%)	⬆️
components/dropdown/dropdown.directive.ts	93.20% <0.00%> (+20.38%)	⬆️
components/menu/submenu-title.component.ts	100.00% <0.00%> (+23.07%)	⬆️
... and 10 more

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