THE ARMY is notifying patients treated by a dentist at Fort Bragg, N.C., who tested positive for the AIDS virus in routine Army screening for the disease . . . A MODERATE EARTHQUAKE, measuring 5.3 on the Richter scale, shook the Hawaiian islands Wednesday, but no injuries or damage were immediately reported . . . SOUTH KOREAN riot police swinging truncheons and firing tear gas fought tens of thousands of radical students and workers Thursday in the largest nationwide anti-government protests in three years. Protests against the fatal beating of a student by police were staged in 87 cities and townships, news reports said.