TUMON, Guam — Passport: check. Coronavirus test: negative. Temperature: normal. Wearing an N95 mask and face shield, Jimmy Lin lugged his bag full of instant noodles and beachwear out of Guam’s modest airport one recent afternoon... ...Like thousands of Asian tourists who have visited this American outpost in the Pacific since early this summer, Lin was in Guam to get his preferred coronavirus shots — Pfizer-BioNTech’s messenger-RNA doses — under a vaccine tourism initiative designed to offset pandemic losses.... ...“I’m a vaccine snob,” said Lin, who got his first Pfizer shot on Aug. 3 through Guam’s government-sponsored “vacation and vaccination,”...