fix(mangler): handle cases where a var is declared in a block scope

[sapphi-red]

This PR fixes the mangler that it was outputting function _() { { var a; let a; } } for function _() { { var x; let y; } }.
This caused this error: https://github.com/oxc-project/monitor-oxc/actions/runs/12962575667/job/36159286596#step:8:31

refs #8705

[sapphi-red]

• fix(mangler): handle cases where a var is declared in a block scope #8706 👈 (View in Graphite)
• main

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[codspeed-hq]

CodSpeed Performance Report

Merging #8706 will degrade performances by 13.79%

_{Comparing 01-25-fix_mangler_handle_cases_where_a_var_is_declared_in_a_block_scope (9756469) with main (f15bdce)}

Summary

❌ 3 regressions
✅ 30 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	mangler[antd.js]	14.2 ms	16.4 ms	-13.79%
❌	mangler[react.development.js]	290 µs	318.1 µs	-8.85%
❌	mangler[typescript.js]	38.1 ms	41.4 ms	-8.19%

[sapphi-red]

Hmm, this perf regression is bigger than I expected 🤔

[Boshen]

Last one in https://github.com/oxc-project/monitor-oxc/actions/runs/12964091325/job/36162446586

[Boshen]

Last one in https://github.com/oxc-project/monitor-oxc/actions/runs/12964091325/job/36162446586

node_modules/.pnpm/istanbul-reports@3.1.7/node_modules/istanbul-reports/lib/html-spa/src/summaryTableLine.js
-            {h && k.indexOf(e + g) >= 0 && h.map((a) => <a {...a} tabSize={i + 2} key={a.file} prefix={e + g + "/"} metricsToShow={j} expandedLines={k} setExpandedLines={l} setFileFilter={n} />)}
+            {h && k.indexOf(e + g) >= 0 && h.map((b) => <a {...b} tabSize={i + 2} key={b.file} prefix={e + g + "/"} metricsToShow={j} expandedLines={k} setExpandedLines={l} setFileFilter={n} />)}

This one is a jsx file, probably don't need to fix it 🤔 Maybe a bug in semantic builder

[sapphi-red]

This one is a jsx file, probably don't need to fix it 🤔

It seems it's because <a /> is not counted as a reference by oxc_semantic. references for a is empty.
https://playground.oxc.rs/#eNo9jktuwzAMRK8icNUChvsBunGLLrPuAbKRVTpRIJMGJeUDQ3cPZcPWRiQ482ZmcNDBkMklz2TsS/9q5iMZfYIpC5kfa+a2bfti3n6PVL6hAYZuBslUv/igZO/QJcnYQPCUtjk6nnBfHmPPYduSWIoDywjdYEPE0sBkJaIsRM7i8OADkh0VAAljai/xrsmToKqu+GcFKa44NdfYxazzzl5pycoJtRNg/Hz/+AJVOP7HE9b2uoye/OBXreOxBih3adXA7ew1fLJOa2xFHVMSDofAt+q5ovQc93spT8WCdZQ=
We can probably fix this by adding support for JSXIdentifier in oxc_semantic.