DETROIT—For the first time in eight months, the global shortage of computer chips won’t force General Motors to close any North American factories. The company said Friday that starting Nov. 1, all plants that had been closed on and off since February because of the shortage will be cranking out vehicles. The nation’s largest automaker and the rest of the global auto industry have been sporadically shutting down plants since late last year due to the semiconductor shortage, which has cut supplies on dealer lots and driven new vehicle prices to record levels. To be sure, production still isn’t back to normal because some of the factories will only run on one shift per day. Phil Amsrud, senior principal analyst for IHS Markit who studies the chip market, said GM’s move is a good sign, but doesn’t signal the end of the chip shortage. “It’s just not a sign that …