62c21a0800
This fixes the (unreported) issue where solo'ing an NLA track would only play back animation when _any_ of the tracks were unmuted. Some code considered a track to be muted when its `NLATRACK_MUTED` flag was set regardless of the `NLATRACK_SOLO` flag, whereas other code did consider the `NLATRACK_SOLO` flag. Now all the code is consistent with what actual animation evaluation is doing. Pull Request: https://projects.blender.org/blender/blender/pulls/134500