*: recalculate the threshold of gctuner when ServerMemoryLimit is updated (#51197)

[ti-chi-bot]

This is an automated cherry-pick of #51197

What problem does this PR solve?

Issue Number: close #48180

Problem Summary:

What changed and how does it work?

recalculate the threshold of gctuner when ServerMemoryLimit is updated.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

I have tested in the production cluster. When I set ServerMemoryLimit , the GOGC will update.

• 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

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (release-6.5@72ae08b). Click here to learn what that means.
The diff coverage is 100.0000%.

Additional details and impacted files

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AilinKid, hawkingrei

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• OWNERS [AilinKid,hawkingrei]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-02-21 06:29:53.882384368 +0000 UTC m=+425082.630007479: ☑️ agreed by hawkingrei.
• 2024-02-21 06:43:19.012383442 +0000 UTC m=+425887.760006553: ☑️ agreed by AilinKid.

[hawkingrei]

/retest