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

[ti-chi-bot]

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[ti-chi-bot]

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Adding the do-not-merge/cherry-pick-not-approved label.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (release-7.1@d1e3dee). Click here to learn what that means.

Additional details and impacted files

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