BTW, practice engine failure by shutting down the engine was/is discouraged due to the number of times such practice led to loss of aircraft and life, the events being far too numerous to list.
The only multi engine training situation I can recall which was actively discouraged, following an increase in training incidents and fatalities, was the old practice of stall training and demonstrations with one engine inoperative.
Shutting down and restarting engines in multi-engine airplanes is still a regular requirement of any inflight training program with which I'm familiar, from primary training to the issuance of type ratings.