[foreign] RFR 8213028: Add windows equivalent for getpid test

[Jorn Vernee]

Hi,

I still had an open ticket for adding a Windows equivalent for the 
getpid test.

The case is pretty interesting because it requires getting the current 
process handle, which is a pointer with a special value (-1). We also 
test that we can call the Windows API. So, I think it's useful to have.

Bug: https://bugs.openjdk.java.net/browse/JDK-8213028
Webrev: 
http://cr.openjdk.java.net/~jvernee/panama/webrevs/8213028/webrev.01/

Thanks,
Jorn