test: add a unit-test for apis/opts/ports.go & add a unit-test for method getSELinuxSecurityOpts in cri_utils.go & add a unit-test for method modifyContainerNamespaceOptions in cri_utils.go

[scuzhangp123]

Ⅰ. Describe what this PR did
add a unit-test for ports.go
add a unit-test for method getSELinuxSecurityOpts in cri_utils.go
add a unit-test for method modifyContainerNamespaceOptions in cri_utils.go

Ⅱ. Does this pull request fix one issue?
fix issues #1906
fix issues #1912
fix issues #1911

Ⅲ. Describe how you did it
Build unit test by condition combination coverage(ccc).

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews
Come from Group 5

[pouchrobot]

We found this is your first time to contribute to Pouch, @scuzhangp123
👏 We really appreciate it.
Just remind that you have read the contribution guide: https://github.com/alibaba/pouch/blob/master/CONTRIBUTING.md
If you didn't, you should do that first. If done, welcome again and please enjoy hacking! 🍻

[codecov-io]

Codecov Report

Merging #1935 into master will increase coverage by 0.14%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1935      +/-   ##
==========================================
+ Coverage    63.3%   63.44%   +0.14%     
==========================================
  Files         200      200              
  Lines       15521    15521              
==========================================
+ Hits         9825     9847      +22     
+ Misses       4456     4427      -29     
- Partials     1240     1247       +7

Flag	Coverage Δ
#criv1alpha1test	33.78% <ø> (+0.02%)	⬆️
#criv1alpha2test	34.24% <ø> (-0.08%)	⬇️
#integrationtest	38.41% <ø> (+0.01%)	⬆️
#unittest	21.22% <ø> (+0.36%)	⬆️

Impacted Files	Coverage Δ
cri/stream/portforward/httpstream.go	69.16% <0%> (-6.67%)	⬇️
cri/stream/runtime.go	71.01% <0%> (-2.9%)	⬇️
ctrd/container.go	51.54% <0%> (-0.69%)	⬇️
cri/v1alpha2/cri.go	66.31% <0%> (-0.18%)	⬇️
daemon/mgr/container.go	53.85% <0%> (-0.16%)	⬇️
daemon/mgr/system.go	76.92% <0%> (+1.7%)	⬆️
ctrd/image.go	78.71% <0%> (+1.98%)	⬆️
cri/v1alpha1/cri_utils.go	77.14% <0%> (+2.85%)	⬆️
ctrd/watch.go	75.75% <0%> (+3.03%)	⬆️
apis/opts/ports.go	56.52% <0%> (+56.52%)	⬆️

[pouchrobot]

@scuzhangp123 Thanks for your contribution. 🍻
Please sign off in each of your commits.

[YaoZengzeng]

Could you please squash your commits and make them more clear? :)

[pouchrobot]

ping @scuzhangp123
Conflict happens after merging a previous commit.
Please rebase the branch against master and push it back again. Thanks a lot.