executor: fix data race because of using shared KV requests (#61376)

[ti-chi-bot]

This is an automated cherry-pick of #61376

What problem does this PR solve?

Issue Number: close #60175

Problem Summary:

What changed and how does it work?

The different coprocessor iterator should run on different KV requests, the share usage can cause data race.

Check List

Tests

• [x] 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

[ti-chi-bot]

@you06 This PR has conflicts, I have hold it. Please resolve them or ask others to resolve them, then comment /unhold to remove the hold label.

[you06]

/retest

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 75.60976% with 10 lines in your changes missing coverage. Please review.

Please upload report for BASE (release-7.1@b28c84d). Learn more about missing BASE report.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-7.1     #61414   +/-   ##
================================================
  Coverage               ?   73.4661%           
================================================
  Files                  ?       1213           
  Lines                  ?     382187           
  Branches               ?          0           
================================================
  Hits                   ?     280778           
  Misses                 ?      83469           
  Partials               ?      17940           

:rocket: New features to boost your workflow:

• :snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• :package: JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cfzjywxk, zyguan

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~~ [cfzjywxk,zyguan]

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[bot]]

[LGTM Timeline notifier]

Timeline:

• 2025-06-18 06:37:18.961190669 +0000 UTC m=+253691.684369651: :ballot_box_with_check: agreed by cfzjywxk.
• 2025-06-18 07:25:21.694367339 +0000 UTC m=+256574.417546313: :ballot_box_with_check: agreed by zyguan.

[you06]

/unhold

[you06]

/retest