planner: fix wrong table filters for index merge plan (#23132)

[ti-srebot]

cherry-pick #23132 to release-5.0-rc
You can switch your code base to this Pull Request by using git-extras:

# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/23166

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/tidb.git pr/23166:release-5.0-rc-9ac5b7ae3669

---

What problem does this PR solve?

Issue Number: close #23112

Problem Summary:

Wrong result for index merge plan.

What is changed and how it works?

What's Changed:

Keep the whole DNF filter if any partial path contains table filters.

Related changes

• Need to cherry-pick to the release branch

Check List

Tests

• Unit test

Side effects

N/A

Release note

• Fix wrong table filters for index merge plan

[ti-srebot]

/run-all-tests

[ti-srebot]

@eurekaka you're already a collaborator in bot's repo.

[eurekaka]

/run-all-tests

[time-and-fate]

/lgtm

[qw4990]

/LGTM

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• qw4990
• time-and-fate

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