test: update test for bun headers

[Hebilicious]

🔗 Linked issue

Resolves #1461

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

I was able to run the header tests locally for bun 0.8.1. However the same tests appear to be failing with the CI.
Investigating, I'm able to make the tests fail locally by downgrading my node version to 16, which match the CI behaviour.
I'm not sure why this is happening, but we can handle this the same way we handle deno

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[codecov]

Codecov Report

Merging #1684 (4a4c519) into main (3315c99) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1684   +/-   ##
=======================================
  Coverage   77.79%   77.79%           
=======================================
  Files          76       76           
  Lines        7836     7836           
  Branches      805      805           
=======================================
  Hits         6096     6096           
  Misses       1738     1738           
  Partials        2        2