buffer: add fast api for isAscii & isUtf8

[anonrig]

Adds v8 fast api for IsUtf8 and IsAscii methods

isAscii benchmark: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/1706/

 confidence improvement accuracy (*) (**) (***)
buffers/buffer-isascii.js input='hello world' length='long' n=20000000 *** 37.08 % ±0.87% ±1.17% ±1.52%
buffers/buffer-isascii.js input='hello world' length='short' n=20000000 *** 36.83 % ±0.86% ±1.15% ±1.51%

isUtf8 benchmark: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/1708/

buffers/buffer-isutf8.js input='∀x∈ℝ: ⌈x⌉ = −⌊−x⌋' length='long' n=20000000 *** 1.95 % ±0.22% ±0.29% ±0.38%
buffers/buffer-isutf8.js input='∀x∈ℝ: ⌈x⌉ = −⌊−x⌋' length='short' n=20000000 *** 65.95 % ±2.35% ±3.13% ±4.08%
buffers/buffer-isutf8.js input='regular string' length='long' n=20000000 *** 42.16 % ±4.05% ±5.39% ±7.02%
buffers/buffer-isutf8.js input='regular string' length='short' n=20000000 *** 121.41 % ±1.15% ±1.54% ±2.02%

[codecov]

Codecov Report

❌ Patch coverage is 76.00000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.16%. Comparing base (723d7bb) to head (6b11f13).
⚠️ Report is 2976 commits behind head on main.

Files with missing lines	Patch %	Lines
src/node_buffer.cc	76.00%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@ Coverage Diff @@## main #58058 +/- ##
==========================================
- Coverage 90.17% 90.16% -0.02% 
==========================================
Files 630 630 Lines 186473 186496 +23 Branches 36613 36614 +1 ==========================================
+ Hits 168160 168162 +2 - Misses 11128 11132 +4 - Partials 7185 7202 +17 

Files with missing lines	Coverage Δ
src/node_buffer.cc	69.20% <76.00%> (+0.10%)	⬆️

... and 24 files with indirect coverage changes

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[mcollina]

lgtm

[lemire]

Great work.

[anonrig]

@jasnell@Renegade334 can you review this pull-request one more time?

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/66565/

[Renegade334]

Might be worth re-running benchmarks, but LGTM 👍

(Needs dont-land-on-v20.x/v22.x, as the old fast API did not provide access to the isolate.)

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/66666/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/66724/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/67660/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/67712/

[jasnell]

The failure in CI here is not a flaky failure. It's relevant to the change being made here. That should be fixed before trying CI again.

[slagiewka]

Looks like this was covered and released in #64169.