[OpenJDK 2D-Dev] RFR: 8055705: Rename UnixPrintServiceLookup and Win32PrintServiceLookup as a platform neutral class name

[Phil Race]

Apparently jigsaw finds it inconvenient that the service provider class 
names
are different for Windows vs the rest of the platforms, so this fix 
basically
just renames both classes to PrintServiceLookupProvider.
I did jprt build on all platforms and tested both Unix and Windows
There's no specific test - just run anything that looks up printers.
https://bugs.openjdk.java.net/browse/JDK-8055705
http://cr.openjdk.java.net/~prr/8055705/
-phil.