builders are in need of re-balancing

```
The 5th newlib builder (the catchall builder) is not taking well over 4 hours!

http://build.chromium.org/p/client.nacl.ports/builders/linux-newlib-4/builds/163
```

Original issue reported on code.google.com by `sbc@google.com` on 11 Jun 2015 at 11:20
