This fixes the following (loop-lennth > internal_playback_seek
length. Due to read-ahead on some cycles the following can happen
---
Loop From: 3528000 To: 3880800 (len: 352800)
start-sample: 3880971 playback_sample: 3528171 nframes: 96
start-sample: 3880875 playback_sample: 3528075 nframes: 192
---
which resulted in disk_samples_to_consume == 0;
4c7cde0242