tests/lavfi: use do_lavfi_pixfmts for the pixdesctest test

Simplify, and as a side effect extend the number of supported formats, in
particular add a test for pal8.

tests/lavfi-regression.sh

@@ -94,16 +94,10 @@ do_lavfi_pixfmts "crop"    "100:100:100:100"
 do_lavfi_pixfmts "hflip"   ""
 do_lavfi_pixfmts "null"    ""
 do_lavfi_pixfmts "pad"     "500:400:20:20"
+do_lavfi_pixfmts "pixdesctest" ""
 do_lavfi_pixfmts "scale"   "200:100"
 do_lavfi_pixfmts "vflip"   ""
 
-if [ -n "$do_pixdesc" ]; then
-    pix_fmts="$($avconv -pix_fmts list 2>/dev/null | sed -ne '9,$p' | grep '^IO' | cut -d' ' -f2 | sort)"
-    for pix_fmt in $pix_fmts; do
-        do_video_filter $pix_fmt "slicify=random,format=$pix_fmt,pixdesctest" -pix_fmt $pix_fmt
-    done
-fi
-
 do_lavfi_lavd() {
     label=$1
     graph=$2

tests/ref/lavfi/pixfmts_pixdesctest

@@ -22,6 +22,7 @@ monob               668ebe8b8103b9046b251b2fa8a1d88f
 monow               9251497f3b0634f1165d12d5a289d943
 nv12                e0af357888584d36eec5aa0f673793ef
 nv21                9a3297f3b34baa038b1f37cb202b512f
+pal8                09b4a6a3167576627fe0540994c3eb24
 rgb0                def2717bc2208505244def3611922d05
 rgb24               b41eba9651e1b5fe386289b506188105
 rgb444be            9e89db334568c6b2e3d5d0540f4ba960