fate: add test for the transpose video filter.

tests/lavfi-regression.sh

@@ -44,6 +44,7 @@ do_lavfi "select"             "select=not(eq(mod(n\,2)\,0)+eq(mod(n\,3)\,0))"
 do_lavfi "setdar"             "setdar=16/9"
 do_lavfi "setsar"             "setsar=16/11"
 do_lavfi "thumbnail"          "thumbnail=10"
+do_lavfi "transpose"          "transpose"
 do_lavfi "vflip"              "vflip"
 do_lavfi "vflip_crop"         "vflip,crop=iw-100:ih-100:100:100"
 do_lavfi "vflip_vflip"        "vflip,vflip"

tests/ref/lavfi/transpose

@@ -0,0 +1 @@
+transpose           cb9cc2b22b0f95f6648fe9ac4d5209a4