Asset prefix is not normalized after upgrade to 15.4.1

[r34son]

Link to the code that reproduces this issue

https://codesandbox.io/p/devbox/youthful-chatelet-4g7njg

To Reproduce

1. run dev
2. see urls for static files in network tab

Current vs. Expected behavior

Current

Nextjs duplicates slashes (for example https://cdn.mydomain.com//_next/static/css/app/page.css?v=17537903)

Expected

No duplication

Provide environment information

Operating System:
  Platform: linux
  Arch: x64
  Version: #1 SMP PREEMPT_DYNAMIC Sun Aug  6 20:05:33 UTC 2023
  Available memory (MB): 4102
  Available CPU cores: 2
Binaries:
  Node: 20.9.0
  npm: 9.8.1
  Yarn: 1.22.19
  pnpm: 8.10.2
Relevant Packages:
  next: 15.4.2-canary.19 // Latest available version is detected (15.4.2-canary.19).
  eslint-config-next: N/A
  react: 19.1.1
  react-dom: 19.1.1
  typescript: 5.3.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Not sure

Which stage(s) are affected? (Select all that apply)

next build (local)

Additional context

After upgrade from 15.3.3 to 15.4.1

[r34son]

@timneutkens Hi Tim! Could you please take a look?