[8] request for review: 7160293: [macosx] FileDialog appears on secondary display

[Dmitry Cherepanov]

Here's a patch for the problem - dialog appears on the wrong monitor.

The minimal patch for this issue would be a one line change in 
nativeGetScreenNSWindowIsOn_AppKitThread (AWTWindow.m):

-    return 1;
+    return index;

but the fix also includes some minor cleanup:

http://cr.openjdk.java.net/~dcherepanov/7160293/webrev.0/

Thanks,
Dmitry