gc: delete TiFlash placement rules in batch (#54071)

[ti-chi-bot]

This is an automated cherry-pick of #54071

What problem does this PR solve?

Issue Number: close #54068

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.

Improve performance of GC worker by deleting TiFlash placement rules in batch

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 2 lines in your changes missing coverage. Please review.

Please upload report for BASE (release-6.5@718cb69). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-6.5     #54409   +/-   ##
================================================
  Coverage               ?   73.6265%           
================================================
  Files                  ?       1096           
  Lines                  ?     352271           
  Branches               ?          0           
================================================
  Hits                   ?     259365           
  Misses                 ?      76231           
  Partials               ?      16675           

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: GMHDBJD, tangenta

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 [GMHDBJD,tangenta]

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

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-07-09 06:35:47.824681821 +0000 UTC m=+339445.059915926: ☑️ agreed by GMHDBJD.
• 2024-07-10 08:17:20.49219982 +0000 UTC m=+431937.727433933: ☑️ agreed by tangenta.