benchmark: add large buffer sizes to buffer-creation

[RajeshKumar11]

Summary

• Adds 10 KiB, 51 KiB, 102 KiB, and 204 KiB to the len parameter of benchmark/buffers/buffer-creation.js
• The existing benchmark only covered sizes up to 8192 bytes (8 KiB); performance regressions in the medium-to-large size range were invisible

Root cause context

Issue #61967 reports significant Buffer.allocUnsafe() regressions in v24 vs v20:

Size	v20.12.1	v24.13.0	Change
10 KiB	1044 ms	996 ms	-5%
51 KiB	1230 ms	1387 ms	+13%
102 KiB	1339 ms	2077 ms	+55%
204 KiB	1969 ms	3349 ms	+70%

The regression is limited to Buffer.allocUnsafe() sizes that bypass the small-allocation pool (≥ 4096 bytes), and shows size-dependent scaling. Adding these sizes to the benchmark makes the regression reproducible and trackable via CI benchmark comparisons.

To run with a smaller iteration count suitable for large sizes:

node benchmark/buffers/buffer-creation.js type=fast-allocUnsafe len=204800 n=10000

Test plan

• node benchmark/buffers/buffer-creation.js continues to work for all existing sizes
• New sizes 10240, 52224, 104448, 208896 can be selected via len= argument

Refs: #61967

[nodejs-github-bot]

Review requested:

• @nodejs/performance

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.76%. Comparing base (da5efc4) to head (94c1142).
⚠️ Report is 16 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61979      +/-   ##
==========================================
+ Coverage   88.84%   89.76%   +0.92%     
==========================================
  Files         674      674              
  Lines      204957   205674     +717     
  Branches    39309    39437     +128     
==========================================
+ Hits       182087   184630    +2543     
+ Misses      15088    13271    -1817     
+ Partials     7782     7773       -9     

Files with missing lines	Coverage Δ
lib/fs.js	98.19% <100.00%> (+4.85%)	⬆️
lib/internal/fs/promises.js	98.73% <100.00%> (+0.67%)	⬆️

... and 187 files with indirect coverage changes

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