planner: Fix the issue that may generate many plandigests when the inner table is clustered (#47952)

[ti-chi-bot]

This is an automated cherry-pick of #47952

What problem does this PR solve?

Issue Number: close #47634
Problem Summary:
After pr:#38259 queries with the same plan have different plan_digest in information_schema.statement_summary

What is changed and how it works?

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.

None

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AilinKid, qw4990

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-12-22 06:31:52.102232153 +0000 UTC m=+1201803.139459125: ☑️ agreed by qw4990.
• 2023-12-22 06:35:05.508792403 +0000 UTC m=+1201996.546019355: ☑️ agreed by AilinKid.

[qw4990]

/test unit-test

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@qw4990: No presubmit jobs available for pingcap/tidb@release-6.5

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/test unit-test

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[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (release-6.5@62766de). Click here to learn what that means.
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Additional details and impacted files

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