BRIGHTON, Mass. — Before the start of the season, Boston College baseball head coach Todd Interdonato did the math. If the Eagles reached the 20-win mark in non-conference play and the 15-win mark in the Atlantic Coast Conference, they would realistically be guaranteed an NCAA Tournament bid. While BC completed the latter of the two milestones earlier in the season — with a 7-6 triumph over Notre Dame on April 26 — it was still looking for a pair of victories heading into this weekend’s series against NJIT to reach 20 wins in out-of-league competition. The No. 22-ranked Eagles did not quite get there by sundown on Sunday, dropping the first game of the series 8-7 before rebounding later in the day with a 6-3 win over the Highlanders (16-28-1, 6-15 AE), but they came close enough, according to Interdonato. “Our guys have done a great job of [not looking big picture] all year,” said Interdonato. “We set out at the beginning of the year to go 20-6 in non-conference, and we went 19-7, right?…