fix: align source name conflict handling

[CPunisher]

Summary

fix #6878

The processing flow of webpack is as follows:

1. Webpack treats each element in sourcemap.sources as a module. (Code)
2. It calculates the module -> sourceName mapping and stores it in moduleToSourceNameMapping. (Code)
3. It checks and resolves conflicts in the values of moduleToSourceNameMapping. (Code)
4. sourceMap.sources = modules.map(m => moduleToSourceNameMapping.get(m)); (Code)

The issue with rspack is that it directly handles conflicts between sourcemap.sources. Even if the same source points to the same module, it will execute the fallback logic and append a query ?xxxx to the original result.

Checklist

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

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[SyMind]

!bench

[rspack-bot]

📝 Benchmark detail: Open

Name	Base (2024-07-02 a22f039)	Current	Change
10000_development-mode + exec	2.16 s ± 22 ms	2.16 s ± 30 ms	-0.23 %
10000_development-mode_hmr + exec	685 ms ± 7.3 ms	688 ms ± 4.9 ms	+0.37 %
10000_production-mode + exec	2.82 s ± 23 ms	2.79 s ± 24 ms	-1.32 %
arco-pro_development-mode + exec	1.9 s ± 47 ms	1.91 s ± 55 ms	+0.54 %
arco-pro_development-mode_hmr + exec	433 ms ± 1.5 ms	433 ms ± 1.4 ms	-0.09 %
arco-pro_production-mode + exec	3.46 s ± 67 ms	3.46 s ± 54 ms	-0.02 %
threejs_development-mode_10x + exec	1.57 s ± 16 ms	1.57 s ± 15 ms	-0.17 %
threejs_development-mode_10x_hmr + exec	797 ms ± 13 ms	798 ms ± 5.9 ms	+0.13 %
threejs_production-mode_10x + exec	5.57 s ± 50 ms	5.61 s ± 24 ms	+0.61 %

[SyMind]

@CPunisher Thank you for your excellent work!