7166437: [macosx] Support for Window.Type.UTILITY on the Mac

Summary: Apply the native UTILITY style for UTILITY Java windows
Reviewed-by: art

src/macosx/classes/sun/lwawt/macosx/CPlatformWindow.java

@@ -312,6 +312,10 @@ public class CPlatformWindow extends CFRetainedResource implements PlatformWindo
             styleBits = SET(styleBits, NONACTIVATING, true);
         }
 
+        if (Window.Type.UTILITY.equals(target.getType())) {
+            styleBits = SET(styleBits, UTILITY, true);
+        }
+
         if (target instanceof javax.swing.RootPaneContainer) {
             javax.swing.JRootPane rootpane = ((javax.swing.RootPaneContainer)target).getRootPane();
             Object prop = null;