ddl: release the limit of reorg worker count

[fzzf678]

What problem does this PR solve?

Release the limit of reorg worker count to see the performance
Issue Number: close #xxx

Problem Summary:

What changed and how does it work?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No need to test

  • I checked and no code files have been changed.

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[tiprow]

Hi @fzzf678. Thanks for your PR.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.9025%. Comparing base (a21c95b) to head (b3951c2).
Report is 20 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #58502        +/-   ##
================================================
+ Coverage   73.5387%   74.9025%   +1.3638%     
================================================
  Files          1681       1726        +45     
  Lines        464263     477045     +12782     
================================================
+ Hits         341413     357319     +15906     
+ Misses       102025      97375      -4650     
- Partials      20825      22351      +1526     

Flag	Coverage Δ
integration	48.7893% <16.6666%> (?)
unit	72.2706% <100.0000%> (-0.0350%)	⬇️

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

Components	Coverage Δ
dumpling	52.6910% <ø> (ø)
parser	∅ <ø> (∅)
br	61.4700% <ø> (+15.6955%)	⬆️

[ti-chi-bot]

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[ti-chi-bot]

[FORMAT CHECKER NOTIFICATION]

Notice: To remove the do-not-merge/needs-linked-issue label, please provide the linked issue number on one line in the PR body, for example: Issue Number: close #123 or Issue Number: ref #456.

_{📖 For more info, you can check the "Contribute Code" section in the development guide.}

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Tests

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_{📖 For more info, you can check the "Contribute Code" section in the development guide.}