Optimize CloneSet event handler codes

[veophi]

Ⅰ. Describe what this PR does

Ⅱ. Does this pull request fix one issue?

Ⅲ. Describe how to verify it

Ⅳ. Special notes for reviews

[codecov-commenter]

Codecov Report

Merging #1219 (5278f75) into master (e70c146) will increase coverage by 0.11%.
The diff coverage is 0.00%.

📣 This organization is not using Codecov’s GitHub App Integration. We recommend you install it so Codecov can continue to function properly for your repositories. Learn more

@@            Coverage Diff             @@
##           master    #1219      +/-   ##
==========================================
+ Coverage   49.99%   50.11%   +0.11%     
==========================================
  Files         143      143              
  Lines       19843    19872      +29     
==========================================
+ Hits         9921     9958      +37     
+ Misses       8834     8818      -16     
- Partials     1088     1096       +8     

Flag	Coverage Δ
unittests	50.11% <0.00%> (+0.11%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/controller/cloneset/cloneset_event_handler.go	66.36% <0.00%> (+7.01%)	⬆️

... and 10 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[zmberg]

/lgtm

[zmberg]

/approve

[kruise-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: zmberg

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [zmberg]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment