ROME — The leader of an Italian party that hopes to capitalize on growing resentment of migrants and asylum-seekers told supporters in Rome on Sunday it would be “splendid” if he wins national elections and his government can issue one-way tickets home to undeserving refugees. Matteo Salvini wants to propel his anti-immigrant Northern League, which was founded in 1991 as a regional party in Italy’s affluent north, to its first premiership in the national election set for early 2018.