Music-time has a significantly reduced resolution.
When evaluating parameter automation using sample-time, different
samples can be mapped back to the same beat-tick. This can result in
endless loops.
The same automation event is found again:
```
start: 112640 next_event.when: b13334 -> dist a5892029@a662323200 in dist.samples: 1002
start: 113642 next_event.when: b13334 -> dist a269@a668214960 dist.samples: 0
```
Note this fix may not be correct, since time-domains are mixed.
"end" is using sample-time. Furthermore The loop is only entered
if there is an event found using timepos_t(start).
Further work will be required (ideally use the same resolution for
all time-domains, or force everything that is evaluated in RT-context
to a single time-domain)
6a55146fdc