rootParams() is now a plain Proimse (not exotic) (vercel#75717)

When we made Request data APIs async we made them exotic to make the
transition to the Promise API easier to adopt because lots of existing
code probably accessed these values synchronously. `rootParams` is a new
Request Data API however and it has no existing usage that is async so
we do not need to support exotic access to these values. This change
removes the exotic construction in favor of a simple resolved Promise.

packages/next/src/server/request/root-params.ts

@@ -43,7 +43,7 @@ export async function unstable_rootParams(): Promise<Params> {
           )
         }
 
-        return makeUntrackedRootParams(underlyingParams)
+        return Promise.resolve(underlyingParams)
       }
       case 'prerender':
       case 'prerender-ppr':
@@ -57,7 +57,7 @@ export async function unstable_rootParams(): Promise<Params> {
       // fallthrough
     }
   }
-  return makeUntrackedRootParams(underlyingParams)
+  return Promise.resolve(underlyingParams)
 }
 
 function createPrerenderRootParams(
@@ -106,7 +106,7 @@ function createPrerenderRootParams(
   }
 
   // We don't have any fallback params so we have an entirely static safe params object
-  return makeUntrackedRootParams(underlyingParams)
+  return Promise.resolve(underlyingParams)
 }
 
 function makeErroringRootParams(
@@ -172,27 +172,3 @@ function makeErroringRootParams(
 
   return promise
 }
-
-function makeUntrackedRootParams(underlyingParams: Params): Promise<Params> {
-  const cachedParams = CachedParams.get(underlyingParams)
-  if (cachedParams) {
-    return cachedParams
-  }
-
-  // We don't use makeResolvedReactPromise here because params
-  // supports copying with spread and we don't want to unnecessarily
-  // instrument the promise with spreadable properties of ReactPromise.
-  const promise = Promise.resolve(underlyingParams)
-  CachedParams.set(underlyingParams, promise)
-
-  Object.keys(underlyingParams).forEach((prop) => {
-    if (wellKnownProperties.has(prop)) {
-      // These properties cannot be shadowed because they need to be the
-      // true underlying value for Promises to work correctly at runtime
-    } else {
-      ;(promise as any)[prop] = underlyingParams[prop]
-    }
-  })
-
-  return promise
-}