Broadway's Tony Awards on June 6 will feature a showdown worthy of a comic-book movie: Vying for best actor in a musical are Hugh Jackman (a.k.a. ''X-Men'''s Wolverine) and Alfred Molina (''Spider-Man 2'' villain Doctor Octavius). Pundits favor Jackman to win the trophy for ''The Boy From Oz'' over Molina in ''Fiddler on the Roof.'' But which of their Hollywood alter egos would reign? Comic-book fans might put their money on Wolverine, but not Avi Arad, chairman-CEO of Marvel Studios, a producer of the ''X-Men'' and ''Spider-Man'' films. ''Both will get badly hurt,'' he says. ''Then they'll come to their senses and just start singing.''