Investigators appointed by the Vatican have been instructed to review each of the 229 Roman Catholic seminaries in the United States for "evidence of homosexuality" and for faculty members who dissent from church teaching, according to a document prepared to guide the process. The Vatican document, given to The New York Times yesterday by a priest, surfaces as Catholics await a Vatican ruling on whether homosexuals should be barred from the priesthood. In a possible indication of the ruling's contents, the American archbishop who is supervising the seminary review said last week that "anyone who has engaged in homosexual activity...