loaders: use pre-compiled loader-runner distributed with Next.js (#3823)
The benefit of this depends on
https://github.com/vercel/next.js/pull/45962, but it remains compatible
with apps including `loader-runner`.
This first attempts to require `loader-runner` from the app's installed
version of Next.js, falling back to requiring the package directly. We
should probably eventually remove this fallback once all compatible
versions of Next.js include the precompiled version, as that has a more
predictable version of the package.
Test Plan: Linked a local copy of Next.js including
https://github.com/vercel/next.js/pull/45962 to an app without
`loader-runner` that uses loaders and verified loaders ran.