buffer: fix negative index for large buffers

[Dansatch]

Fixes #66294.

Buffer.prototype.indexOf() returned a negative position when a match occurred beyond 2 GiB because the result was converted to a signed 32-bit integer.

This change returns the position as a JavaScript number and adds regression tests for number, Buffer, and string searches.

[github-actions]

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[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 90.37%. Comparing base (c0681e5) to head (04a1fd7).
⚠️ Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
src/node_buffer.cc	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66325      +/-   ##
==========================================
- Coverage   90.37%   90.37%   -0.01%     
==========================================
  Files         790      790              
  Lines      274514   274514              
  Branches    52572    52570       -2     
==========================================
- Hits       248102   248089      -13     
- Misses      16889    16921      +32     
+ Partials     9523     9504      -19     

Files with missing lines	Coverage Δ
src/node_buffer.cc	70.33% <80.00%> (-0.09%)	⬇️

... and 29 files with indirect coverage changes

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