The University of Massachusetts at Amherst said Monday it would review a program that drafts students as confidential drug informants, The Boston Globereported, in the wake of a Globe article Sunday that described the death of one such informant from a heroin overdose. The original Globe article focused on why students who work for the university in that capacity -- some of whom have been caught using drugs -- get appropriate treatment for addictions and are exempted from UMass requirements that the parents of students who violate campus rules on drugs or alcohol are informed.