Cleanup unused vtorc code

[dbussink]

This was found with deadcode, probably after the cleanup done in #15580.

Related Issue(s)

Follow up after #15580.

Checklist

• "Backport to:" labels have been added if this change should be back-ported to release branches
• If this change is to be back-ported to previous releases, a justification is included in the PR description
• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on CI?
• Documentation was added or is not required

[vitess-bot]

Review Checklist

Hello reviewers! 👋 Please follow this checklist when reviewing this Pull Request.

General

• Ensure that the Pull Request has a descriptive title.
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Tests

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Documentation

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Backward compatibility

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• If a flag is removed, then it should also be removed from vitess-operator and arewefastyet, if used there.
• vtctl command output order should be stable and awk-able.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 65.80%. Comparing base (696fe0e) to head (0a3e6f4).
Report is 165 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #15595      +/-   ##
==========================================
- Coverage   67.41%   65.80%   -1.62%     
==========================================
  Files        1560     1560              
  Lines      192752   194758    +2006     
==========================================
- Hits       129952   128157    -1795     
- Misses      62800    66601    +3801     

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