"Penny Wise Pound Foolish" is a term that's very close to this. In other words, per your example, they want to save 12 cents per unit on a run of 20 million units, but then because the part was made cheaply, a customer dies etc.
This kind of discussion floats around business classes all the time, though I don't recall hearing about a fancy term like your suggested "gallows engineering". From outside the company when they do that, such as a friend of the dead customer, the phrase "cheap ass bastards" also comes pretty close.