feat: add rust benchmark case for code splitting

[JSerFeng]

Summary

Add rust benchmark for code splitting

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[netlify]

✅ Deploy Preview for rspack canceled.

Name	Link
🔨 Latest commit	c00591e
🔍 Latest deploy log	https://app.netlify.com/sites/rspack/deploys/67972bb6e07b4c00086b8f14

[codspeed-hq]

CodSpeed Performance Report

Merging #9127 will not alter performance

_{Comparing bench/new-code-splitting (c00591e) with main (b40fb8c)}

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Summary

✅ 2 untouched benchmarks
🆕 4 new benchmarks
⁉️ 2 (👁 2) dropped benchmarks

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
🆕	basic	N/A	2.6 ms	N/A
🆕	basic_sourcemap	N/A	2.8 ms	N/A
👁	basic	2.6 ms	N/A	N/A
👁	basic_sourcemap	2.8 ms	N/A	N/A
🆕	build_chunk_graph	N/A	88.1 ms	N/A
🆕	build_chunk_graph_parallel	N/A	67.9 ms	N/A