fate/mp=pp: remove dering subfilter test.

This subfilter gives a different output when linesize and width are
differents.

tests/lavfi-regression.sh

@@ -49,9 +49,9 @@ do_lavfi "idet"               "idet"
 do_lavfi "null"               "null"
 do_lavfi "overlay"            "split[m],scale=88:72,pad=96:80:4:4[o2];[m]fifo[o1],[o1][o2]overlay=240:16"
 do_lavfi "pad"                "pad=iw*1.5:ih*1.5:iw*0.3:ih*0.2"
-do_lavfi "pp"                 "mp=pp=be/hb/vb/dr/tn/l5/al"
-do_lavfi "pp2"                "mp=pp=be/fq:16/h1/v1/dr/lb"
-do_lavfi "pp3"                "mp=pp=be/fq:8/ha:128:7/va/dr/li"
+do_lavfi "pp"                 "mp=pp=be/hb/vb/tn/l5/al"
+do_lavfi "pp2"                "mp=pp=be/fq:16/h1/v1/lb"
+do_lavfi "pp3"                "mp=pp=be/fq:8/ha:128:7/va/li"
 do_lavfi "pp4"                "mp=pp=be/ci"
 do_lavfi "pp5"                "mp=pp=md"
 do_lavfi "pp6"                "mp=pp=be/fd"

tests/ref/lavfi/pp

@@ -1 +1 @@
-pp                  8e68fb247880aa083e91bcbddf9d76c7
+pp                  62a6acf1969155f29249fd0757540f9f

tests/ref/lavfi/pp2

@@ -1 +1 @@
-pp2                 28e91376aeb49c79dae9221b1a4997ae
+pp2                 efcfe545df8f869e3a93ae25a3e08967

tests/ref/lavfi/pp3

@@ -1 +1 @@
-pp3                 d8d19c1f5e3f4032e9ed7bbb2026f030
+pp3                 39af1a30d0ea0e906df264773adfcaa6