BUDAPEST — Just weeks before Hungary’s parliamentary election, a court is expected to rule on a case that has come to symbolize Prime Minister Viktor Orbán’s anti-migrant agenda for both his supporters and opponents. The court in the southern city of Szeged is due to give its verdict in the retrial of a Syrian man convicted of terrorism and jailed for 10 years for his role in a confrontation between police and asylum seekers on the border with Serbia in 2015.