fix: Rspack dev gets stuck after removing a page (#80555)
Rspack's incremental build algorithm causes a situation where deleted
entries in dynamic entries still get built.
If a page is deleted, an infinite loop occurs in the corresponding
`next-app-loader`, causing the entire compilation to hang.
The root cause of the hang lies in `const resolvedPagePath = await
resolver(matchedPagePath)` failing to resolve `resolvedPagePath`,
preventing the loop from exiting.
When `resolvedPagePath` doesn't exist, we should immediately throw an
Error. This logic would also benefit webpack, as scenarios where pages
are deleted during the execution of `next-app-loader` do occur.
