Scale external program icons to 16x16

GTK3 API gtk_icon_theme_lookup_by_gicon() returns 48x48 icons,
despite specifying size 16x16 in the arguments.

This change scales the retrieved icon to 16x16,
to avoid unexpected program icon sizes.

Fixes: #3003

Author: trancexpress

bundles/org.eclipse.swt/Eclipse SWT Program/gtk/org/eclipse/swt/program/Program.java

@@ -204,6 +204,8 @@ public ImageData getImageData(int zoom) {
 					}
 				}
 				data.alphaData = alphaData;
+				ImageData scaled = data.scaledTo(16, 16);
+				data = scaled;
 			} else {
 				PaletteData palette = new PaletteData(0xFF0000, 0xFF00, 0xFF);
 				data = new ImageData(width, height, 24, palette, 4, srcData);