segfault running custom next server within jest unit test after upgrading nextjs 11 -> 12

Run next info (available from version 12.0.8 and up)

N/A

What version of Next.js are you using?

11.1.3 + 12.0.7

What version of Node.js are you using?

16.13.1

What browser are you using?

N/A

What operating system are you using?

macOS

How are you deploying your application?

N/A

Describe the Bug

Within a custom server application there are some unit tests using the jest framework along with supertest to mimic http requests (See replication repo). This has been working as expected up until trying to upgrade to multiple 12.X nextjs versions including 12.0.0, 12.0.1, and 12.0.7.

When running version 12 with a next.config.js configuration present and a custom server with dev: false, the jest execution exits with a segfault when calling app.prepare().

const app = next({
      dev: false,
});

await app.prepare(); // Goes 💥

zsh: segmentation fault  npm test

It is possible to workaround this issue by importing the nextjs config manually and passing it as the conf option to the custom next application.

example workaround

const app = next({
      dev: false,
      conf: require('./next.config'), // this fixes the seg fault
});

await app.prepare(); // No 💥 this time

await request(app.getRequestHandler())
      .get("/")
      .expect(200);

Expected Behavior

I would expect this not to crash and nextjs to be able to resolve the next.config.js automatically without the conf option

To Reproduce

I have published a public GitHub repo that reproduces the following scenarios along with setup instructions

https://github.com/Kauabunga/nextjs-replicate-segfault-custom-server-v12

1. [✓] jest unit test with version 11.1.3 without a next.config.js
2. [✓] jest unit test with version 11.1.3 with a next.config.js
3. [✓] jest unit test with version 12.0.7 without a next.config.js
4. [✗] jest unit test with version 12.0.7 with a next.config.js
5. [✓] jest unit test with version 12.0.7 with a next.config.js with custom server options conf: require('next.config')
6. [✗] jest unit test with version canary with a next.config.js and segfault-handler

[khasty720]

Same issue reported here https://github.com/vercel/next.js/issues/31162

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