planner: fixing wrong result after applying predicate push down for CTEs (#47891)

[ti-chi-bot]

This is an automated cherry-pick of #47891

What problem does this PR solve?

Issue Number: close #47881

Problem Summary:

What is changed and how it works?

The outerMost should be prop of the CTE itself, not the CTE reader's.

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.

Fix the issue that TiDB may push wrong predicates into the CTE.

[elsa0520]

LGTM

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-11-01 12:16:14.58605083 +0000 UTC m=+3041772.173160975: ☑️ agreed by elsa0520.
• 2023-11-01 12:36:07.97967503 +0000 UTC m=+3042965.566785173: ☑️ agreed by time-and-fate.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AilinKid, elsa0520, time-and-fate

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[winoros]

/retest