improved performance of the inital is-this-a-module check (also works around a bug)
improved performance of the inital is-this-a-module check (also works around a bug)

svn: r5643

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket