br: continuing retry when pitr met the error about memory is limited

[joccau]

What problem does this PR solve?

Issue Number: close #41983

Problem Summary:

• If the config tikv.import.memory-use-ratio is too low, tikv-server would report the error "memory is limited" to BR when PITR restore, and the PITR restore failed finally because the retry times exceeds the threshold.

What is changed and how it works?

Check List

Tests

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

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 the issue that failed to restore log with the error "memory is limited".

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• 3pointer
• YuJuncen

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[3pointer]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 893f76f

[joccau]

/rebuild

[joccau]

/run-all-tests

[joccau]

/test unit-test

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #41995.