Chemical Compositions, and Antimicrobial and Mosquito Larvicidal Activities of Essential Oils from Four Syzygium Species Syzygium formosum (Wall.) Masam., S. syzygioides (Miq.) Merr. & L.M. Perry, S. megacarpum (Craib) Rathakr. & N.C. Nair, and S. chantaranothaianum W.K. Soh & J. Parn