feat(minifier): normalize Number.NaN as NaN

[Boshen]

closes #11272

[graphite-app]

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[Boshen]

Merge activity

• May 25, 4:06 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• May 25, 5:19 AM UTC: Boshen added this pull request to the Graphite merge queue.
• May 25, 5:25 AM UTC: Merged by the Graphite merge queue.

[Copilot]

Pull Request Overview

This PR normalizes the representation of NaN by converting both NaN and Number.NaN expressions to a unified f64::NaN.

• Adds tests to ensure that Number.NaN is normalized to NaN.
• Updates normalization logic in the minifier to handle Number.NaN alongside NaN.
• Introduces a helper method in the AST builder to construct a NaN literal.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
crates/oxc_minifier/tests/peephole/dead_code_elimination.rs	Adds tests for folding Number.NaN to NaN.
crates/oxc_minifier/src/peephole/normalize.rs	Updates normalization documentation and adds fold_number_nan_to_nan function; renames convert_void_ident to fold_void_ident.
crates/oxc_ast/src/ast_builder_impl.rs	Introduces a new nan() helper function to build a NaN literal.

[codspeed-hq]

CodSpeed Instrumentation Performance Report

Merging #11275 will degrade performances by 5.07%

_{Comparing 05-25-feat_minifier_normalize_number.nan_as_nan_ (f88f666) with main (7f2d660)}

Summary

❌ 1 regressions
✅ 37 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	mangler[RadixUIAdoptionSection.jsx]	13.6 µs	14.3 µs	-5.07%