querystring: precompute Latin-1 escapes

[rozzilla]

Precompute percent-encoded strings for the 128 non-ASCII Latin-1 characters instead of joining two byte escapes on every occurrence. This reduces repeated work when querystring and URLSearchParams serialize query parameters containing characters such as é. Other character ranges are unchanged; the tradeoff is a fixed 128-entry lookup table.

Benchmarks on Apple M2/macOS against dd7235c show higher throughput

• Existing heavily encoded querystring.stringify workload (+31.9%)
• Dense Latin-1 querystring.escape workloads (+48–56%)
• Fresh URLSearchParams construction and serialization (+25–49% for dense Latin-1 and +4–11% for mixed ASCII/Latin-1)

Across 48 cases and 5,760 samples, eight gains in both comparisons were confirmed after Holm correction, with no statistically significant regressions, including startup controls.

[nodejs-github-bot]

Review requested:

• @nodejs/performance

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.50%. Comparing base (dd7235c) to head (bcfe0f4).
⚠️ Report is 10 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66756      +/-   ##
==========================================
+ Coverage   90.48%   90.50%   +0.01%     
==========================================
  Files         791      797       +6     
  Lines      277204   277509     +305     
  Branches    53311    53323      +12     
==========================================
+ Hits       250841   251165     +324     
+ Misses      16760    16750      -10     
+ Partials     9603     9594       -9     

Files with missing lines	Coverage Δ
lib/internal/querystring.js	100.00% <100.00%> (ø)

... and 46 files with indirect coverage changes

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