expression: ignore TypeNULL in HandleBinaryLiteral (#49527)

[ti-chi-bot]

This is an automated cherry-pick of #49527

What problem does this PR solve?

Issue Number: close #49526

Problem Summary:

What changed and how does it work?

Ignore the TypeNull in HandleBinaryLiteral, as the castStringToString will actually do nothing for NULL (except changing the type).

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

None

[YangKeao]

/retest

[YangKeao]

LGTM

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lcwangchao, YangKeao

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-12-21 07:52:29.120620929 +0000 UTC m=+1120240.157847841: ☑️ agreed by lcwangchao.
• 2023-12-21 07:53:09.086441134 +0000 UTC m=+1120280.123668063: ☑️ agreed by YangKeao.