Log Message:
Update lang/nodejs4 to 4.8.1.

- buffer: The performance of .toJSON() is now up to 2859% faster on
  average.
- IPC: Batched writes have been enabled for process IPC on platforms
  that support Unix Domain Sockets.
  - Performance gains may be up to 40% for some workloads.
- http: Control characters are now always rejected when using
  http.request().
- node: Heap statistics now support values larger than 4GB.