fix: fix the logic for the UNDICI_NO_WASM_SIMD environment variable

[ShenHongFei]

Rationale

The original function of the UNDICI_NO_WASM_SIMD environment variable was reversed. It has been fixed now.

Changes

Fixed the erroneous logic of UNDICI_NO_WASM_SIMD

Features

N/A

Bug Fixes

N/A

Breaking Changes and Deprecations

N/A

Status

• I have read and agreed to the Developer's Certificate of Origin
• [S] Tested
• [S] Benchmarked (optional)
• [S] Documented
• Review ready
• In review
• Merge ready

[codecov-commenter]

Codecov Report

❌ Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 93.03%. Comparing base (6824eed) to head (11f65ab).

Files with missing lines	Patch %	Lines
lib/dispatcher/client-h1.js	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5026      +/-   ##
==========================================
- Coverage   93.04%   93.03%   -0.02%     
==========================================
  Files         110      110              
  Lines       35793    35793              
==========================================
- Hits        33305    33301       -4     
- Misses       2488     2492       +4     

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[mcollina]

cc @Uzlopak @richardlau this seems correct. Wdyt?

[richardlau]

FWIW we can probably rework the assumption to disable by default on Power now as the V8 fix has been backported to all in support LTS Node.js release lines, but I guess we'd need an allow list of Node.js versions as Undici might be being run on an older, e.g. Node.js 24 release before the fix went in.