fate: add and fix subtitles dependencies.

tests/fate/subtitles.mak

-FATE_SUBTITLES += fate-sub-jacosub
+FATE_SUBTITLES_ASS-$(call DEMDEC, JACOSUB, JACOSUB) += fate-sub-jacosub
 fate-sub-jacosub: CMD = md5 -i $(SAMPLES)/sub/JACOsub_capability_tester.jss -f ass
 
-FATE_SUBTITLES += fate-sub-microdvd
+FATE_SUBTITLES_ASS-$(call DEMDEC, MICRODVD, MICRODVD) += fate-sub-microdvd
 fate-sub-microdvd: CMD = md5 -i $(SAMPLES)/sub/MicroDVD_capability_tester.sub -f ass
 
-FATE_SUBTITLES += fate-sub-movtext
+FATE_SUBTITLES_ASS-$(call DEMDEC, MOV, MOVTEXT) += fate-sub-movtext
 fate-sub-movtext: CMD = md5 -i $(SAMPLES)/sub/MovText_capability_tester.mp4 -f ass
 
-FATE_SUBTITLES += fate-sub-movtextenc
+FATE_SUBTITLES-$(call ENCDEC, MOVTEXT, MOV) += fate-sub-movtextenc
 fate-sub-movtextenc: CMD = md5 -i $(SAMPLES)/sub/MovText_capability_tester.mp4 -map 0 -scodec mov_text -f mp4 -flags +bitexact -movflags frag_keyframe+empty_moov
 
-FATE_SUBTITLES += fate-sub-realtext
+FATE_SUBTITLES_ASS-$(call DEMDEC, REALTEXT, REALTEXT) += fate-sub-realtext
 fate-sub-realtext: CMD = md5 -i $(SAMPLES)/sub/RealText_capability_tester.rt -f ass
 
-FATE_SUBTITLES += fate-sub-sami
+FATE_SUBTITLES_ASS-$(call DEMDEC, SAMI, SAMI) += fate-sub-sami
 fate-sub-sami: CMD = md5 -i $(SAMPLES)/sub/SAMI_capability_tester.smi -f ass
 
-FATE_SUBTITLES-$(call DEMDEC, SRT, SRT) += fate-sub-srt
+FATE_SUBTITLES_ASS-$(call DEMDEC, SRT, SUBRIP) += fate-sub-srt
 fate-sub-srt: CMD = md5 -i $(SAMPLES)/sub/SubRip_capability_tester.srt -f ass
 
-FATE_SUBTITLES += fate-sub-subripenc
+FATE_SUBTITLES-$(call ALLYES, MOV_DEMUXER MOVTEXT_DECODER SUBRIP_ENCODER) += fate-sub-subripenc
 fate-sub-subripenc: CMD = md5 -i $(SAMPLES)/sub/MovText_capability_tester.mp4 -scodec subrip -f srt
 
-FATE_SUBTITLES += fate-sub-subviewer
+FATE_SUBTITLES_ASS-$(call DEMDEC, SUBVIEWER, SUBVIEWER) += fate-sub-subviewer
 fate-sub-subviewer: CMD = md5 -i $(SAMPLES)/sub/SubViewer_capability_tester.sub -f ass
 
-FATE_SUBTITLES += fate-sub-webvtt
+FATE_SUBTITLES_ASS-$(call DEMDEC, WEBVTT, WEBVTT) += fate-sub-webvtt
 fate-sub-webvtt: CMD = md5 -i $(SAMPLES)/sub/WebVTT_capability_tester.vtt -f ass
 
+FATE_SUBTITLES-$(call ENCMUX, ASS, ASS) += $(FATE_SUBTITLES_ASS-yes)
 FATE_SUBTITLES += $(FATE_SUBTITLES-yes)
 
 FATE_SAMPLES_FFMPEG += $(FATE_SUBTITLES)