PHOENIX — Enter the Chandler Fashion Mall southeast of Phoenix and a big, vertical advertisement stops you in your tracks with three white letters highlighted against a black background: WTF. Step close and faint gray letters explain the acronym: WATTS TO FREEDOM. The GMC Hummer EV supertruck has landed. Imagine 205-kilowatt-hour battery, 1,000 horsepower, 9,000 pounds, 35-inch all-terrain tires. Three electric motors. All-wheel steering. Faster than a speeding bullet, more powerful than a locomotive, able to leap tall buildings in a single bound. WTF, indeed. Strapped into my Hummer tester ou…