tests: fix TestScatterRegions

[rleungx]

What problem does this PR solve?

Issue Number: Close #7109.

What is changed and how does it work?

also fix

[2025/02/26 09:39:09.226 +00:00] [INFO] [cluster.go:1751] ["auto gc the tombstone store success"] [store="id:1 address:\"localhost:1\" state:Tombstone physically_destroyed:true node_state:Removed "] [down-time=483489h39m9.226474515s]

Check List

Tests

• Unit test

Release note

None.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.31%. Comparing base (ecb9a61) to head (781831b).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9108      +/-   ##
==========================================
+ Coverage   76.28%   76.31%   +0.03%     
==========================================
  Files         473      473              
  Lines       71663    71663              
==========================================
+ Hits        54665    54689      +24     
+ Misses      13566    13552      -14     
+ Partials     3432     3422      -10     

Flag	Coverage Δ
unittests	76.31% <ø> (+0.03%)	⬆️

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lhy1024, okJiang

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-02-28 05:54:16.529936081 +0000 UTC m=+594404.483094342: ☑️ agreed by lhy1024.
• 2025-03-03 04:02:41.014317166 +0000 UTC m=+241474.143236906: ☑️ agreed by okJiang.