Watching Angelina Jolie slice, dice, kick, jump, shoot, run, and blow stuff up, all while camera-ready has its moments. The idea of a 110-pound action star with ropy arms, Claes Oldenburg lips, and a bosom Roger Corman would love made sense only on the pages of a comic book. But Jolie operates in ridiculous defiance of physics. In “Salt,’’ she plays Evelyn Salt, an American spy on the run for, perhaps, being a Russian double agent. At some point, it looks as though she’s been cornered and caught. But, no: She leaps off an overpass onto a moving semi, then onto a tanker, followed by a delivery truck, then a motorbike. She hangs off a speeding vehicle, forces a poor police officer to drive while she Tases him, and goes rolling off a bulleting subway. For 45 minutes as a blonde, for 45 as a steely brunette.