By Anthony Boadle BRASILIA (Reuters) -Former Brazilian President Luiz Inacio Lula da Silva holds a solid polling lead going into Sunday’s election against incumbent Jair Bolsonaro, with a chance of clinching the race in the first round, fresh surveys showed on Saturday. Brazil’s most polarized election in decades will decide whether to return to power the leftist leader who spent time in jail on corruption convictions or the right-wing populist who has attacked the voting system and threatened to contest defeat. Two polls released on Saturday showed Lula with a majority of valid votes, which w…