A track index in an Ogg file means the same stream everywhere: the
file's order, as `tracks` lists them. Streams the native path does not
read fell back to symphonia with the same index, but symphonia orders
tracks by serial, which ffmpeg picks at random. A file could decode the
wrong track, or fail on a FLAC stream listed before an Opus one.
The tests write each file eight times, so both serial orders occur, and
cover a track with no mask comment next to one with a mask.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>