RFR: 8000975: Merge UNIXProcess.java.bsd & UNIXProcess.java.linux

[Rob McKenna]

It has been suggested to me (at least twice at this stage) that these 
files should be merged since they're identical. This requires an 
adjustment in perspective from "every platform should have its own 
implementation" to "those platforms that differ from the norm should 
have their own implementation". Given that the latter approach 
simplifies things currently I believe it is the more sensible.

Webrev at:
http://cr.openjdk.java.net/~robm/8000975/webrev.01/ 
<http://cr.openjdk.java.net/%7Erobm/8000975/webrev.01/>

    -Rob