Transient language test failure in time extension

The following testing error occurs from time to time. It it usually does not recur re-run.

- time::TimeModelMouseDiscreteEvent *** FAILED ***

The test is in extensions/time/tests.txt

```
TimeModelMouseDiscreteEvent
  OPEN> extensions/time/examples/MouseDiscreteEvent.nlogo
  O> setup
  O> start
```