fix metadata url resolving with path posix (#57343)
x-ref: [https://dev.azure.com/nextjs/next.js/_build/results?buildId=71881&view=logs&jobId=8[…]-584d-6f5c-57bad8880974&t=7ae70e63-3625-50f4-6764-5b3e72b4bd7a](https://dev.azure.com/nextjs/next.js/_build/results?buildId=71881&view=logs&jobId=8af7cf9c-43a1-584d-6f5c-57bad8880974&j=8af7cf9c-43a1-584d-6f5c-57bad8880974&t=7ae70e63-3625-50f4-6764-5b3e72b4bd7a)
Follow up for: https://github.com/vercel/next.js/pull/57265
