Allow our node server to have lots of sockets open.
Allow our node server to have lots of sockets open.

1024 isn't enough for a high-powered server such as ours!  Maybe.

When you're root, you can set the num-fd limit as high as you want,
but otherwise 2048 is the max.  We try for either.

Auditors: jlfwong

Test plan:
Ran 'npm start' without error.

Khan/react-render-server,Khan/react-render-server,Khan/react-render-server