*: fix cte nil pointer error when got multiple apply

[guo-shaoge]

What problem does this PR solve?

Issue Number: close #44774

Problem Summary:
The following plan:

Apply-1
    outerSide
    Apply-2
        CTE-1(access CTEProducer-1)
        CTE-2(access CTEProducer-1)

CTEProducer-1 has corCol, which is one of columns of Apply-1's outerSide output)

If CTE-1 and CTE-2 both access the same CTE Producer(a.k.a. same CTE defition), we use CTEExec.IsInApply to control whether reopen CTEStorage.

But CTE.IsInApply is not enough here, because CTE-1 and CTE-2 only need to reopen when Apply-1 runs, no need to reopen when Apply-2 runs.

What is changed and how it works?

Before: Always reopen CTEStorage/CTEProducer when CTE.IsInApply is true.

After: Only reopen CTEStorage/CTEProducer when the data of corCol changes.

Check List

Tests

• Unit test
• Integration test: https://github.com/pingcap/tidb-test/pull/2159
• 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

[guo-shaoge]

/test check_dev2

[ti-chi-bot]

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[guo-shaoge]

/test check-dev2

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AilinKid, wjhuang2016

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-06-20 06:53:23.337705548 +0000 UTC m=+85768.738955996: ☑️ agreed by AilinKid.
• 2023-06-20 08:45:37.666690036 +0000 UTC m=+92503.067940474: ☑️ agreed by wjhuang2016.

[guo-shaoge]

/test build
/test unit-test

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.4: #44840.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.1: #44842.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #44844.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #44846.