player/loadfile: limit playlist size to 10 for fuzzing

Fixes timeout on huge generated playlists, 10 is enough to test if it
works.

player/loadfile.c

@@ -1564,6 +1564,11 @@ static void play_current_file(struct MPContext *mpctx)
 
     reset_playback_state(mpctx);
 
+#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+    if (mpctx->playlist->num_entries > 10)
+        goto terminate_playback;
+#endif
+
     mpctx->playing = mpctx->playlist->current;
     assert(mpctx->playing);
     assert(mpctx->playing->filename);