statistics: fix wrong behavior for primary key' non-lite init stats (#53298)

[ti-chi-bot]

This is an automated cherry-pick of #53298

What problem does this PR solve?

Issue Number: ref #37548

Problem Summary:

What changed and how does it work?

primary key's is_index is false. so it cannot load the topn. it's stats cannon be set as AllFull.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

according to #37548, it's result is right.

• 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@cefc9ec). Click here to learn what that means.

Additional details and impacted files

@@               Coverage Diff                @@
##             release-8.1     #53304   +/-   ##
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  Coverage               ?   71.1441%           
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  Files                  ?       1465           
  Lines                  ?     421218           
  Branches               ?          0           
================================================
  Hits                   ?     299672           
  Misses                 ?     101067           
  Partials               ?      20479           

Flag	Coverage Δ
unit	71.1441% <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	40.9738% <0.0000%> (?)

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-05-16 00:15:07.079060158 +0000 UTC m=+1698660.836195728: ☑️ agreed by hawkingrei.
• 2024-05-16 01:53:25.6256846 +0000 UTC m=+1704559.382820173: ☑️ agreed by qw4990.