perf: remove unneeded string clone

[JSerFeng]

Summary

Remove some unneeded string allocation.

Checklist

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

[JSerFeng]

!bench

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[rspack-bot]

📝 Benchmark detail: Open

Name	Base (2024-07-10 7d3eabb)	Current	Change
10000_development-mode + exec	2.19 s ± 24 ms	2.16 s ± 26 ms	-1.15 %
10000_development-mode_hmr + exec	692 ms ± 5.3 ms	689 ms ± 7 ms	-0.35 %
10000_production-mode + exec	2.84 s ± 18 ms	2.77 s ± 21 ms	-2.18 %
arco-pro_development-mode + exec	1.9 s ± 85 ms	1.88 s ± 65 ms	-1.25 %
arco-pro_development-mode_hmr + exec	434 ms ± 2.3 ms	433 ms ± 1.2 ms	-0.18 %
arco-pro_production-mode + exec	3.41 s ± 86 ms	3.44 s ± 85 ms	+0.89 %
threejs_development-mode_10x + exec	1.59 s ± 10 ms	1.57 s ± 18 ms	-1.48 %
threejs_development-mode_10x_hmr + exec	799 ms ± 11 ms	794 ms ± 5.3 ms	-0.54 %
threejs_production-mode_10x + exec	5.61 s ± 40 ms	5.51 s ± 23 ms	-1.72 %

[chenjiahan]

Please add some descriptions 😄