br: fix checkpoint cannot advance after pause->stop->start (#53091)

[ti-chi-bot]

This is an automated cherry-pick of #53091

What problem does this PR solve?

Issue Number: close #53047
Problem Summary:

What changed and how does it work?

When advancer stop a task, the isPaused would be marked as false

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.

fix when checkpoint cannot advance after pause->stop->start

[RidRisR]

/test unit-test

[tiprow]

@RidRisR: No presubmit jobs available for pingcap/tidb@release-6.5

In response to this:

/test unit-test

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (release-6.5@fe6837a). Click here to learn what that means.

Additional details and impacted files

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: BornChanger, Leavrth

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• OWNERS [Leavrth]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-05-10 04:02:21.039199251 +0000 UTC m=+1193894.796334823: ☑️ agreed by Leavrth.
• 2024-05-10 07:35:00.366395522 +0000 UTC m=+1206654.123531096: ☑️ agreed by BornChanger.