scheduler: optimize performance on transformer extension and Skip status

[saintube]

Ⅰ. Describe what this PR does

Improve scheduler performance by several small changes.

Ⅱ. Does this pull request fix one issue?

Ⅲ. Describe how to verify it

Ⅳ. Special notes for reviews

V. Checklist

• I have written necessary docs and comments
• I have added necessary unit tests and integration tests
• All checks passed in make test

[codecov]

Codecov Report

Attention: Patch coverage is 87.80488% with 5 lines in your changes missing coverage. Please review.

Project coverage is 67.72%. Comparing base (c6cddf3) to head (c9f28f3).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/scheduler/frameworkext/framework_extender.go	91.42%	2 Missing and 1 partial ⚠️
pkg/scheduler/plugins/elasticquota/plugin.go	0.00%	1 Missing ⚠️
pkg/scheduler/plugins/reservation/scoring.go	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2211      +/-   ##
==========================================
+ Coverage   67.70%   67.72%   +0.01%     
==========================================
  Files         446      446              
  Lines       42719    42739      +20     
==========================================
+ Hits        28925    28946      +21     
- Misses      11271    11272       +1     
+ Partials     2523     2521       -2     

Flag	Coverage Δ
unittests	67.72% <87.80%> (+0.01%)	⬆️

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[ZiMengSheng]

/lgtm

[hormes]

/approve