Fix weak box tests for optional `weak-box-value' argument; add one for the new functionality.
Fix weak box tests for optional `weak-box-value' argument; add one for the new functionality.

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