Create Buffer.copy static method

[araujogui]

Fixes #53700

[codecov]

Codecov Report

❌ Patch coverage is 86.59794% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.52%. Comparing base (4f24aff) to head (90e196e).
⚠️ Report is 112 commits behind head on main.

Files with missing lines	Patch %	Lines
src/node_buffer.cc	67.50%	7 Missing and 6 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61168      +/-   ##
==========================================
- Coverage   88.53%   88.52%   -0.01%     
==========================================
  Files         703      704       +1     
  Lines      208546   208797     +251     
  Branches    40217    40283      +66     
==========================================
+ Hits       184634   184840     +206     
- Misses      15926    15944      +18     
- Partials     7986     8013      +27     

Files with missing lines	Coverage Δ
lib/buffer.js	99.85% <100.00%> (-0.15%)	⬇️
src/node_buffer.cc	69.18% <67.50%> (+0.30%)	⬆️

... and 72 files with indirect coverage changes

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[bakkot]

There's been some efforts (notably by @jasnell) to bring the native JS buffer/TA types into alignment with Buffer, at least for major use cases. See also #41588.

Adding new functionality to Buffer seems contrary to that effort. I'm not necessarily opposed, but it's probably worth thinking through what it would look like for this functionality to exist in pure JS, or alternatively what alternatives would exist in JS such that it would enable people to migrate away from use of Buffer.

[araujogui]

@bakkot I created and verified with benchmarks, and you're right. The standard Web API dst.set(new Uint8Array(src)) consistently outperforms this PR.

Since the standard approach is both more idiomatic and more performant, there’s no reason to add more surface area to Buffer.

I guess we can close this PR