br: Enable checkpoint advancer to pause tasks lagged too large (#51441)

[ti-chi-bot]

This is an automated cherry-pick of #51441

What problem does this PR solve?

Issue Number: close #50803

Problem Summary:

What changed and how does it work?

Now, a new option called CheckPointLagLimit is added to the advancer config. When it is set, advancer will check if the checkpoint is lagged too large on every tick. If so, advancer would send a warning to PD and unstall the task.
PS: Theoretically, we need a resume signal when the task could be resumed. However, there is no channel to send this signal now. Maybe we will add it in the future.

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.

A new option called `CheckPointLagLimit` is added to the advancer config. When it is set, advancer will check if the checkpoint is lagged too large on every tick. If so, advancer would send a warning to PD and unstall the task.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (release-7.1@eae093d). Click here to learn what that means.
The diff coverage is 59.5959%.

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, YuJuncen

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• OWNERS [YuJuncen]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-04-18 03:02:56.091656425 +0000 UTC m=+479995.202702875: ☑️ agreed by BornChanger.
• 2024-04-18 03:08:45.941872073 +0000 UTC m=+480345.052918521: ☑️ agreed by YuJuncen.

[BornChanger]

/retest