Documents emerged Thursday that showed a conflicting picture of how Elizabeth Warren’s ethnicity has been defined throughout her years as a student and prominent academic. Several newly unearthed student and personnel records from the schools at which she taught or attended show that Warren either listed herself as white, or did not mention ethnicity at all. But the University of Pennsylvania, where Warren intermittently taught law school from 1987 through 1995, touted Warren as a minority faculty member in an official school publication, according to an online document obtained by The Boston Globe.