planner: fix bug in PhysicalTableReader::Clone() (#45302)

[ti-chi-bot]

This is an automated cherry-pick of #45302

What problem does this PR solve?

Issue Number: close #45299

Problem Summary:

What is changed and how it works?

Fix PhysicalTableReader::Clone, so PhysicalTableReader::TablePlans are still extracted from PhysicalTableReader::tablePlan

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.

None

[windtalker]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: SeaRise, windtalker

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-07-13 03:18:06.050387929 +0000 UTC m=+561177.820726632: ☑️ agreed by windtalker.
• 2023-07-13 03:39:48.991546201 +0000 UTC m=+562480.761884913: ☑️ agreed by SeaRise.

[windtalker]

/test unit-test

[tiprow]

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

In response to this:

/test unit-test

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