6853488: REGRESSION : A black background is seen for a transparent animated gif image for splash screen

Reviewed-by: igor, prr

jdk/src/share/native/sun/awt/splashscreen/splashscreen_gif.c

@@ -277,7 +277,7 @@ SplashDecodeGif(Splash * splash, GifFileType * gif)
                 ImageRect dstRect;
                 rgbquad_t fillColor = 0;                        // 0 is transparent
 
-                if (transparentColor > 0) {
+                if (transparentColor < 0) {
                     fillColor= MAKE_QUAD_GIF(
                         colorMap->Colors[gif->SBackGroundColor], 0xff);
                 }