Fix link not being GC'd sometimes (#49318)
The `app-link-gc` module should treat the link with just pathname as the
href and full URL as the same resource. This avoids duplicate styles
during HMR:
<img width="482" alt="CleanShot 2023-05-05 at 18 12 12@2x"
src="https://user-images.githubusercontent.com/3676859/236511257-af510ed2-8e21-430a-bf71-24931b10e5de.png">
[Related bug report
(internal)](https://vercel.slack.com/archives/C03KAR5DCKC/p1683295788069859).
