statistics: add gc in hot peer cache

[lhy1024]

What problem does this PR solve?

Issue Number: Close #8698

What is changed and how does it work?

Check List

Tests

• Unit test

Release note

None.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.77%. Comparing base (48e72f1) to head (f2d03a9).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8702      +/-   ##
==========================================
+ Coverage   71.70%   71.77%   +0.07%     
==========================================
  Files         517      517              
  Lines       67450    67477      +27     
==========================================
+ Hits        48364    48432      +68     
+ Misses      15521    15487      -34     
+ Partials     3565     3558       -7     

Flag	Coverage Δ
unittests	71.77% <100.00%> (+0.07%)	⬆️

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