avformat/movenc: read track title from correct key

da9cc22d allowed the MOV muxer to relay a custom stream handler name,
whether populated from the input stream or user-set. However, the entry
key didn't match the key set by the MOV demuxer, so it wasn't
effective. Fixed.

Due to the change, four FATE refs have to be updated. Verified that the
target payload of the tests hasn't changed in terms of CRC.

libavformat/movenc.c

@@ -2599,7 +2599,7 @@ static int mov_write_hdlr_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack *tra
             // of the track. So if an alternate handler description is
             // specified, use it.
             AVDictionaryEntry *t;
-            t = av_dict_get(track->st->metadata, "handler", NULL, 0);
+            t = av_dict_get(track->st->metadata, "handler_name", NULL, 0);
             if (t && utf8len(t->value))
                 descr = t->value;
         }

tests/ref/fate/binsub-movtextenc

-af6a8f38d7c11d9af7823cc44554d2ad
+66b25412f7ca699ee525ba162246edb6

tests/ref/fate/copy-psp

-cada61453a2483ef8ba1fb82c8bbff25 *tests/data/fate/copy-psp.psp
-2041433 tests/data/fate/copy-psp.psp
+65a177552e03123c9a62ddb942970d05 *tests/data/fate/copy-psp.psp
+2041445 tests/data/fate/copy-psp.psp
 #extradata 0:       51, 0xaf6d1012
 #extradata 1:        2, 0x00b200a1
 #tb 0: 1/90000

tests/ref/fate/copy-trac236

-d6e3d97b522ce881ed29c5da74cc7e63 *tests/data/fate/copy-trac236.mov
-630810 tests/data/fate/copy-trac236.mov
+8b57d14c14bb4cdaca660d161e08eb8f *tests/data/fate/copy-trac236.mov
+630861 tests/data/fate/copy-trac236.mov
 #tb 0: 100/2997
 #media_type 0: video
 #codec_id 0: rawvideo

tests/ref/lavf-fate/mov_qtrle_mace6

-dcc9c4c182a5809dee9a9366f4533797 *./tests/data/lavf-fate/lavf.mov
-1270387 ./tests/data/lavf-fate/lavf.mov
+f9715cc38a3206bcdf105786905255af *./tests/data/lavf-fate/lavf.mov
+1270415 ./tests/data/lavf-fate/lavf.mov
 ./tests/data/lavf-fate/lavf.mov CRC=0x9320cd26