refactor(sourcemap): enable_source_map using Arc<str> instead of String

[underfin]

The source_name using String caused more memory allocate at rolldown, here using Arc<str> to avoid this.

[codspeed-hq]

CodSpeed Performance Report

Merging #2779 will improve performances by 6.04%

_{Comparing underfin:refactor-enable_source_map (c32a27e) with main (64e4de7)}

Summary

⚡ 2 improvements
✅ 32 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	underfin:refactor-enable_source_map	Change
⚡	codegen_sourcemap[react.development.js]	15.1 ms	14.2 ms	+6.04%
⚡	codegen_sourcemap[typescript.js]	1.5 s	1.4 s	+4.37%

[Boshen]

Arc feels so weird here, I wonder whether we can change the API and pass in a reference somewhere. Codegen doesn't really need to own the source map name ...

[underfin]

I want to avoid CodegenOptions to CodegenOptions<'a>, as it will be caused Codegen<'a>. What do you think about
change Codegen::new(source_text: &str, options: CodegenOptions) to Codegen::new(source_name &str, source_text: &str, options: CodegenOptions).

[Boshen]

Codegen::new(source_name &str, source_text: &str, options: CodegenOptions) seems better, shall we try this one?

Should it be a filename or a file path though, feels like it should be a &Path?

[underfin]

Should it be a filename or a file path though, feels like it should be a &Path?

The &str is enough for it, the rolldown could cast it or other tools.