hint: avoid duplicate hints in QBHintHandler

[hawkingrei]

What problem does this PR solve?

Issue Number: close #53767

Problem Summary:

What changed and how does it work?

QBHintHandler may produce duplicate hints. When it reaches the match stage, the first one will be marked as a hint, but the second one will be ignored, ultimately resulting in incorrect warning messages.

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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Needs approval from an approver in each of these files:

• OWNERS [AilinKid,qw4990]
• pkg/planner/OWNERS [AilinKid,qw4990]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-06-11 07:07:13.296534427 +0000 UTC m=+448387.349846343: ☑️ agreed by qw4990.
• 2024-06-11 09:15:37.341052882 +0000 UTC m=+456091.394364807: ☑️ agreed by AilinKid.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 55.2055%. Comparing base (5c0d737) to head (7256025).
Report is 5 commits behind head on master.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #53921         +/-   ##
=================================================
- Coverage   72.6403%   55.2055%   -17.4349%     
=================================================
  Files          1508       1628        +120     
  Lines        431735     602407     +170672     
=================================================
+ Hits         313614     332562      +18948     
- Misses        98856     246778     +147922     
- Partials      19265      23067       +3802     

Flag	Coverage Δ
integration	21.6428% <100.0000%> (?)
unit	71.4570% <100.0000%> (-0.1812%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	52.9656% <ø> (ø)
parser	∅ <ø> (∅)
br	50.4082% <ø> (+8.2377%)	⬆️

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #53934.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #53935.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #53936.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.1: #53937.