planner: fix wrong empty projection (#53235) | tidb-test=pr/2331

[ti-chi-bot]

This is an automated cherry-pick of #53235

What problem does this PR solve?

Issue Number: close #49109

Problem Summary:

Projection is wrongly pruned to a empty one after the second round of column pruning

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.

None

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (release-8.1@08aae2a). Click here to learn what that means.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-8.1     #53241   +/-   ##
================================================
  Coverage               ?   71.3151%           
================================================
  Files                  ?       1465           
  Lines                  ?     422233           
  Branches               ?          0           
================================================
  Hits                   ?     301116           
  Misses                 ?     100682           
  Partials               ?      20435           

Flag	Coverage Δ
unit	71.3151% <100.0000%> (?)

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

Components	Coverage Δ
dumpling	53.9957% <0.0000%> (?)
parser	∅ <0.0000%> (?)
br	40.9941% <0.0000%> (?)

[winoros]

/retest

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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• OWNERS [AilinKid,winoros]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-05-14 12:28:00.64680256 +0000 UTC m=+1569834.403938176: ☑️ agreed by AilinKid.
• 2024-05-14 13:45:36.887144777 +0000 UTC m=+1574490.644280350: ☑️ agreed by winoros.