In a key scene halfway through “Hamlet 2,” a downtrodden Arizona high school theater teacher named Dana Marschz (Steve Coogan), whose raunchy, quasi-autobiographical play has raised the ire of the local community, gets his confidence boosted by Cricket Feldstein (Amy Poehler), a fiery representative from the American Civil Liberties Union. With a twinge of excitement, Cricket explains that the school’s attempt to suppress his work constitutes a First Amendment violation, and he stands a good chance of winning out. As she leaves, Dana notes that, by the way, the play is …