### What?
We currently dedupe fetch requests, but if those fetch requests contain a `revalidate` time, when that window is expired all of those fetches will be invoked without deduping.
### Why?
We track revalidations on the `staticGenerationStore` but we don't have a way to dedupe them, as it's currently just an array. When the (patched) fetch is invoked and catches a stale entry, it'll push each fetch onto the `pendingRevalidates` array which will later be invoked via `Promise.all`.
### How?
This updates the shape of `pendingRevalidates` to be a map, that way we can reliably dedupe if we see a key that is already pending revalidation.
Closes NEXT-1744
[slack x-ref](https://vercel.slack.com/archives/C03S8ED1DKM/p1700836529460289)
A shared incremental cache IPC server was introduced for build-time static workers as an optimization to dedupe fetch requests, however this can cause fetch-related flakiness to builds under certain conditions (e.g., large payloads).
This moves the optimization behind an experimental flag to unblock those running into IPC-related build time errors while we work on an alternative solution for the underlying issue
Fixes#53695
This attempts to fix an issue where fetch requests were not being
deduped on the first request to the page (but subsequent requests were
properly deduped).
This seems to be caused by the async context from
`staticGenerationStore` being lost by the time the patched fetch is
called, and so it was falling back to a regular fetch and skipping the
cache. This attempts to fix that by falling back to
`fetch.__nextGetStaticStore()`.
[slack
x-ref](https://vercel.slack.com/archives/C03KAR5DCKC/p1691007445597619)
