It has been true for years: Mile for mile, it’s cheaper — generally much cheaper — to recharge an electric vehicle than it is to refuel one with an internal-combustion engine. That has been a key selling point for Tesla and other EV makers, particularly in times when gas prices have soared, such as now. But this time there’s a wrinkle: While gas prices have indeed soared in the wake of Russia’s invasion of Ukraine, so have electricity prices — particularly in some parts of the U.S. that have been big markets for Tesla’s EVs. That raises a question: Is...