Over 200 Ukrainian specialists are in the Persian Gulf right now, training forces of US allies on how to take down Iranian killer drones.  Ever since Russia invaded Ukraine in 2014, Riyadh and its neighbors hedged carefully between Washington, Beijing and Moscow. Last month, Saudi Arabia signed a 10-year strategic defense agreement with Ukraine. So did Qatar. So did the United Arab Emirates. The countries that bought American for decades are now buying Ukrainian, too. The Saudis figured it out first. The world produces fewer than 900 Patriot missiles a year, while Tehran can churn about 10,000 Shaheds a month. “Mismatch” doesn’t begin to cover it. A Ukrainian interceptor drone can stop a Shahed for around $10,000. A Patriot missile costs $4 million, and hundreds of them were used up in the first days of the confrontation with Iran.  Smoke billows after the recent Ukrainian drone attack on the Tuapse oil refinery in Russia. AFP via Getty Images Riyadh signed the deal with Kyiv on March 27.…