Action hero Liam Neeson is lining up behind Christine Quinn for mayor. “I am proud to endorse Chris Quinn to be our next mayor,” Neeson said this week. “I was an amateur boxer before I was an actor — and I know a good fighter when I see one. No one will work harder than Chris Quinn for New Yorkers who need a fierce advocate in City Hall.” Neeson and Quinn have rubbed elbows before: She presented the “Taken” star with the Thomas Manton Irish Man of the Year Award in March. (Northern Irish-born Neeson is a US citizen.) At the time he quipped, “There’s a popular assumption that actors are very good public speakers. It’s absolute BS. It’s actually my worst nightmare.”