Adapt jest transform for node-only files

Summary:
This changes the jest preprocessor so that files targetet at node.js will be run with the node-specific transform.
It also adapts tests that relied on inline requires.

Benefit: packager tests run faster now.

Reviewed By: cpojer

Differential Revision: D3562007

fbshipit-source-id: e06c86d545926a5c546458025f505dca115e7ea8