Fix data race in coordinator

[hongyunyan]

What problem does this PR solve?

Issue Number: close #xxx

What is changed and how it works?

fix the data race problem found in https://github.com/pingcap/ticdc/actions/runs/13850441995/job/38756721999?pr=961

Check List

Tests

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

Questions

Will it cause performance regression or break compatibility?

Do you need to update user documentation, design documentation or monitoring documentation?

Release note

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If you don't think this PR needs a release note then fill it with `None`.

[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.

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: asddongmen

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-03-14 06:53:52.65258443 +0000 UTC m=+511588.258113357: ☑️ agreed by asddongmen.

[hongyunyan]

/retest

[hongyunyan]

/test pull-cdc-mysql-integration-heavy

[hongyunyan]

/test pull-cdc-mysql-integration-heavy

[hongyunyan]

/test pull-cdc-mysql-integration-heavy

[hongyunyan]

/test pull-cdc-mysql-integration-light

[hongyunyan]

/test pull-cdc-mysql-integration-heavy

[hongyunyan]

/test pull-cdc-mysql-integration-light

[ti-chi-bot]

@hongyunyan: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-cdc-mysql-integration-heavy	85ac3b7	link	true	/test pull-cdc-mysql-integration-heavy
pull-cdc-mysql-integration-light	85ac3b7	link	true	/test pull-cdc-mysql-integration-light

Full PR test history. Your PR dashboard.

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