avformat/matroskadec: Add a fate test for CodecPrivate compression

This test contains a track with zlib compressed CodecPrivate in addition
to compressed frames; the former was unchecked before.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

tests/fate/matroska.mak

@@ -12,6 +12,11 @@ fate-matroska-remux: REF = e5457e5fa606d564a54914bd12f426c8
 FATE_MATROSKA-$(call ALLYES, MATROSKA_DEMUXER VORBIS_PARSER) += fate-matroska-xiph-lacing
 fate-matroska-xiph-lacing: CMD = framecrc -i $(TARGET_SAMPLES)/mkv/xiph_lacing.mka -c:a copy
 
+# This tests that the matroska demuxer supports decompressing
+# zlib compressed tracks (both the CodecPrivate as well as the actual frames).
+FATE_MATROSKA-$(call ALLYES, MATROSKA_DEMUXER ZLIB) += fate-matroska-zlib-decompression
+fate-matroska-zlib-decompression: CMD = framecrc -i $(TARGET_SAMPLES)/mkv/subtitle_zlib.mks -c:s copy
+
 FATE_MATROSKA_FFPROBE-$(call ALLYES, MATROSKA_DEMUXER) += fate-matroska-spherical-mono
 fate-matroska-spherical-mono: CMD = run ffprobe$(PROGSSUF)$(EXESUF) -show_entries stream_side_data_list -select_streams v -v 0 $(TARGET_SAMPLES)/mkv/spherical.mkv
 

tests/ref/fate/matroska-zlib-decompression

+#extradata 0:      348, 0x5f625922
+#tb 0: 1/1000
+#media_type 0: subtitle
+#codec_id 0: dvd_subtitle
+0,       1000,       1000,     1991,      191, 0x52f74934