restore: retry scatter error

[YuJuncen]

What problem does this PR solve?

fix #1400

What is changed and how it works?

Add a retry on scatter failure, instead of giving up scattering the region directly.

Check List

Tests

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

In a workload with little huge tables, many retries were captured.

Release note

• Fix a bug that caused regions spread unbalanced after the restoration.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• 3pointer
• zwj-coder

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[YuJuncen]

/merge

[ti-chi-bot]

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

Commit hash: a400f4b