fix PLT_VALIDATE_COMPILE interaction with 3-D code
fix PLT_VALIDATE_COMPILE interaction with 3-D code

Makes the "optimize.rktl" test suite pass when PLT_VALIDATE_COMPILE
is defined.

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