Run export child process with runtime's default `max-old-space-size`#78712

We ended up always forwarding `NODE_OPTIONS` even if the callsites of `new Worker` removed `max-old-space-size` on purpose like https://github.com/vercel/next.js/blob/e3adfeb8160041f697840c94671cb141a0a40039/packages/next/src/build/index.ts#L753-L767 did. This will also fix a bunch of "port is already in use" issues when you set `NODE_OPTIONS=--inspect`. ## Test plan `NODE_OPTIONS=--max-old-space-size=4096` and then `console.log('worker NODE_OPTIONS', process.env.NODE_OPTIONS)` in `packages/next/src/build/worker.ts`