planner: fix tiflash path will be identified as table dual (#49338)

[ti-chi-bot]

This is an automated cherry-pick of #49338

What problem does this PR solve?

Issue Number: close #49285

Problem Summary:

What changed and how does it work?

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.

planner: fix tiflash path will be identified as table dual

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AilinKid, qw4990

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [AilinKid,qw4990]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-12-22 07:08:52.142692727 +0000 UTC m=+1204023.179919655: ☑️ agreed by AilinKid.
• 2023-12-22 07:42:59.616653918 +0000 UTC m=+1206070.653880845: ☑️ agreed by qw4990.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (release-6.5@859fade). Click here to learn what that means.
The diff coverage is n/a.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-6.5     #49396   +/-   ##
================================================
  Coverage               ?   73.9564%           
================================================
  Files                  ?       1087           
  Lines                  ?     351339           
  Branches               ?          0           
================================================
  Hits                   ?     259838           
  Misses                 ?      75042           
  Partials               ?      16459           

[AilinKid]

/test unit-test

[tiprow]

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

In response to this:

/test unit-test

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[AilinKid]

/test unit-test

[tiprow]

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

In response to this:

/test unit-test

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.