Fix edge rewrite handling (#40115)

Follow-up to #40076 this ensures we handle rendering correctly when the URL doesn't match the edge function exactly e.g. when rewriting since it looks like we don't currently have access to the `x-matched-path` header like we do for serverless functions. 

## Bug

- [ ] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`

Fixes: https://github.com/vercel/next.js/runs/8102187444?check_suite_focus=true

Co-authored-by: Jiachi Liu <inbox@huozhi.im>

Author: ijjk

packages/next/server/base-server.ts

@@ -1578,6 +1578,18 @@ export default abstract class Server<ServerOptions extends Options = Options> {
           if (result !== false) return result
         }
       }
+
+      // currently edge functions aren't receiving the x-matched-path
+      // header so we need to fallback to matching the current page
+      // when we weren't able to match via dynamic route to handle
+      // the rewrite case
+      // @ts-expect-error extended in child class web-server
+      if (this.serverOptions.webServerConfig) {
+        // @ts-expect-error extended in child class web-server
+        ctx.pathname = this.serverOptions.webServerConfig.page
+        const result = await this.renderPageComponent(ctx, bubbleNoFallback)
+        if (result !== false) return result
+      }
     } catch (error) {
       const err = getProperError(error)