The phased group of a non-interruptive phased test is the event

Today NIE tests have the phase group equal to the NonInterruptive or Asynchroneous. Instead it may be better if we set it to the event.

Following cases exist

| Shuffled | Event Defined | Phase Group | Comment |
| -------- | -------------- | ------------ | ---------- |
| FALSE | TRUE | ni_event_``_stepName | |
| FALSE | FALSE | phased-singleRun | If no event is defined the test is executed in DEFAULT/NON_PHASED mode |
| TRUE | TRUE | Nni_event_``_`IDX` | (preferable step name)|
| TRUE | FALSE | phased-singleRun | If no event is defined the test is executed in DEFAULT/NON_PHASED mode |

Start by locating where non-interruptive phased tests assign their phase group, then trace how event definitions and shuffled execution are handled. Compare the behavior with each row in the issue's table; done means the phase group uses the event and step or index when defined, and phased-singleRun when it is not.

Written by the indexing model from the issue text.