RFR 9: 8003488 Add Process.getPid

[roger riggs]

Hi,

The webrev has been updated to more completely describe the pid:
"The native process id is an identification number that the operating 
system assigns to the process."

Any other comments?

Webrev: http://cr.openjdk.java.net/~rriggs/webrev-getpid-8003488/ 
<http://cr.openjdk.java.net/%7Erriggs/webrev-getpid-8003488/>
Issue: https://bugs.openjdk.java.net/browse/JDK-8003488

Thanks, Roger