test: tolerate async block count updates in test-fs-stat-bigint

[RafaelGSS]

Attempt to fix flaky test.

Refs: #57797
Refs: nodejs/reliability#1657

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.43%. Comparing base (554dd55) to head (ea0710f).
⚠️ Report is 43 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66576      +/-   ##
==========================================
- Coverage   90.44%   90.43%   -0.01%     
==========================================
  Files         791      791              
  Lines      276486   276484       -2     
  Branches    53092    53088       -4     
==========================================
- Hits       250060   250050      -10     
  Misses      16846    16846              
- Partials     9580     9588       +8     

see 27 files with indirect coverage changes

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[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/78248/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/78251/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/78254/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/78277/

[nodejs-github-bot]

Landed in 45b9f05