statistics: fix wrong pointer used when async load stats

[winoros]

What problem does this PR solve?

Issue Number: close #51856

Problem Summary:

What changed and how does it work?

The newly created column stats is colHist instead of c.

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

Merging #52169 (a6abee7) into master (7a2f1cc) will decrease coverage by 16.0388%.
Report is 1 commits behind head on master.
The diff coverage is 100.0000%.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #52169         +/-   ##
=================================================
- Coverage   70.7383%   54.6995%   -16.0388%     
=================================================
  Files          1489       1600        +111     
  Lines        439999     609650     +169651     
=================================================
+ Hits         311248     333476      +22228     
- Misses       109286     252952     +143666     
- Partials      19465      23222       +3757     

Flag	Coverage Δ
integration	36.5939% <20.0000%> (?)
unit	70.4498% <100.0000%> (-0.0996%)	⬇️

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

Components	Coverage Δ
dumpling	53.9957% <ø> (ø)
parser	∅ <ø> (∅)
br	51.5864% <ø> (+5.7329%)	⬆️

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hawkingrei, hi-rustin

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-03-28 01:01:14.579905605 +0000 UTC m=+2116101.602151993: ☑️ agreed by hi-rustin.
• 2024-03-28 02:46:16.031733351 +0000 UTC m=+2122403.053979734: ☑️ agreed by hawkingrei.