EMERGING MARKETS-Most Asian FX, stocks gain as China's COVID situation improves

* Asian markets look past China slowdown * Vietnamese dong hits lowest in over a year * Thailand’s GDP grows 2.2% in Q1 By Riya Sharma May 17 (Reuters) – Most Asian currencies and stocks were broadly higher on Tuesday, buoyed by optimism over China’s improving COVID-19 situation, while a weaker dollar and a fall in U.S. Treasury yields overnight also boosted investor sentiment. Equities in Philippines and Indonesia edged up more than 1% each, while South Korea’s won led gains among the Asian currencies. Shares in Thailand climbed 1.6% while the baht was up nearly 0.6%, after Southeast Asia’s…