Re-require all module information for client-side initializers list (#7571)

* Re-require all module information for client-side initializers list
We really should re-work how our loadable code words, because this passes an excessive number of modules to the client.

In the ideal world, we only pass the entry module id of each chunk, but there's no point in investing the time until we switch to webpack 5 which completely revamps the chunk graph API.

* Get a unique set of ids

packages/next-server/server/render.tsx

@@ -473,7 +473,9 @@ export async function renderToHTML(
   const dynamicImports = [
     ...getDynamicImportBundles(reactLoadableManifest, reactLoadableModules),
   ]
-  const dynamicImportsIds: any = dynamicImports.map(bundle => bundle.id)
+  const dynamicImportsIds: any = [
+    ...new Set(dynamicImports.map(bundle => bundle.id)),
+  ]
   const amphtml = isAmp(ampMode)
   const hasAmp = !amphtml && ampMode.enabled
   // update renderOpts so export knows it's AMP

packages/next/build/webpack/plugins/react-loadable-plugin.ts

@@ -61,11 +61,6 @@ function buildManifest(
               manifest[request] = []
             }
 
-            // Avoid duplicate files
-            if (manifest[request].some(item => item.file === file)) {
-              continue
-            }
-
             manifest[request].push({
               id,
               name,