next.js

8b9aa2dc - add experimental flag to allow forcing NODE_ENV=development in builds (#65463)

add experimental flag to allow forcing NODE_ENV=development in builds (#65463) For debugging purposes, it can be useful to set `NODE_ENV=development` during a `next build`. Currently this value is forced to be production in Next.js. This PR adds an experimental flag to not force a mode of `production` when the flag is set. To use this flag, you'll still need to explicitly set `NODE_ENV=development`, while also enabling `nextConfig.experimental.allowDevelopmentBuild` Closes NEXT-3277