fix(minifier): omit dce undefined which can be a shadowed variable

[Boshen]

 // Shadowed `undefined` as a variable should not be erased.
    test(
        "function foo(undefined) { if (!undefined) { } }",
        "function foo(undefined){if(!undefined){}}",
    );

I'm not using the cheap ident.reference_id.get().is_some() here yet because I don't know what I'm doing - how should minifier consume Semantic?

[graphite-app]

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[Boshen]

Passed tests in Rolldown.

[codspeed-hq]

CodSpeed Performance Report

Merging #4073 will not alter performance

_{Comparing 07-07-fix_minifier_omit_dce_undefined_which_can_be_a_shadowed_variable (fd255e9) with main (adee728)}

Summary

✅ 28 untouched benchmarks