This ensures we handle encoding/decoding for SSG prerendered/fallback pages correctly. Since we only encode path delimiters when outputting to the disk we need to match this encoding when building the `ssgCacheKey` to look-up the prerendered pages. This also fixes non-ascii prerendered paths (e.g. 商業日語) not matching correctly. 

This does not resolve 👉  https://github.com/vercel/next.js/issues/10084 and further investigation will be needed before addressing non-ascii paths for non-SSG pages. 

The encoding output was tested against https://tst-encoding-l7amu5b9c.vercel.app/ to ensure the values will match correctly on Vercel. 

Closes: https://github.com/vercel/next.js/issues/17582
Closes: https://github.com/vercel/next.js/issues/17642
x-ref: https://github.com/vercel/next.js/pull/14717