Are "2 engine failures" a part of the training curriculum in a B737/777 etc type rating course ?
Every type rating course I have undergone (5, all in the UK, 2,3,4 engines) involves practising "loss of all engines" from a suitable cruise FL. It is important to be able to recognise the difference between that scenario and "loss of all generators" (with all engines still running) - indications are usually fairly similar, and you may not notice all-engine flameout until the generators drop off-line (eg in descent at idle thrust).
The exercise may end after relighting one/all engines or continue to a landing with one or two engines inop - but in some cases (my A320 course) in addition an all engine out landing is practised as well, depending on the airline.