fix template invocation

Author: ForsakenHarmony

packages/next/src/build/webpack/loaders/next-middleware-loader.ts

@@ -38,7 +38,11 @@ export default async function middlewareLoader(this: any) {
     middlewareConfig: middlewareConfigBase64,
   }: MiddlewareLoaderOptions = this.getOptions()
   const matchers = encodedMatchers ? decodeMatchers(encodedMatchers) : undefined
-  const stringifiedPagePath = stringifyRequest(this, absolutePagePath)
+  const pagePath = this.utils.contextify(
+    this.context || this.rootContext,
+    absolutePagePath
+  )
+
   const middlewareConfig: MiddlewareConfig = JSON.parse(
     Buffer.from(middlewareConfigBase64, 'base64').toString()
   )
@@ -57,7 +61,7 @@ export default async function middlewareLoader(this: any) {
   }
 
   return await loadEntrypoint('middleware', {
-    VAR_USERLAND: stringifiedPagePath,
+    VAR_USERLAND: pagePath,
     VAR_DEFINITION_PAGE: page,
   })
 }