By Marie Mannes STOCKHOLM (Reuters) -Volvo Cars smashed third-quarter profit forecasts on Thursday, despite tariffs and tough competition, as sweeping cost cuts delivered faster than expected results, sending its shares soaring as much as 40%. Volvo's new management - led by CEO Hakan Samuelsson who returned earlier this year - has spent the past six months slashing costs to counter faltering profits. The company cut 3,000 jobs, pulled guidance and slowed investments to offset pressure from U.S. tariffs ...