dillon1000/react

Copy from build to node_modules instead of linking to builds (#26210)

Using the `link:` protocol to create a dependency doesn't work when we
edit the `package.json` to lock the version to a specific version. It
didn't really work before neither, it was just that `yarn` installed an
existing `scheduler` dependency from npm instead of using the built one.

So I'm updating all the fixture to use the technique where we copy files
instead.