deps: use non-SIMD llhttp on the RISC-V architecture

[hrw]

There is no support for RISC-V in undici/llhttp yet so test fails:

Test failed: test//es-module/test-wasm-web-api.js
Test failure message:
node:internal/process/promises:394
    triggerUncaughtException(err, true /* fromPromise */);
    ^
[TypeError: fetch failed] {
  [cause]: HTTPParserError: Response does not match the HTTP/1.1 protocol (Invalid header value char)
      at Parser.createError (node:internal/deps/undici/undici:7417:16)
      at Parser.execute (node:internal/deps/undici/undici:7378:26)
      at Parser.readMore (node:internal/deps/undici/undici:7341:16)
      at Socket.onHttpSocketReadable (node:internal/deps/undici/undici:7821:22)
      at Socket.emit (node:events:514:28)
      at emitReadable_ (node:internal/streams/readable:845:12)
      at process.processTicksAndRejections (node:internal/process/task_queues:89:21) {
    code: undefined,
    data: 'Oct 2026 22:38:29 GMT\r\n' +
      'Connection: keep-alive\r\n' +
      'Keep-Alive: timeout=5\r\n' +
      'Content-Length: 41\r\n' +
      '\r\n' +
      '\x00asm\x01\x00\x00\x00\x01\x07\x01`\x02\x7F\x7F\x01\x7F\x03\x02\x01\x00\x07\x07\x01\x03add\x00\x00\n' +
      '\t\x01\x07\x00 \x00 \x01j\x0B'
  }
}

Use of non-SIMD version make test pass.

Observed in NodeJS 24.21.0 version.

[nodejs-github-bot]

Review requested:

• @nodejs/security-wg

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[richardlau]

This change needs to be made in https://github.com/nodejs/undici otherwise it is going to get overwritten by the automation that updates undici in Node.js.

[richardlau]

Also @nodejs/platform-riscv64 since this doesn't seem to be something that has already been mentioned in nodejs/build#4099.

[hrw]

Reported as nodejs/undici#6041