racket/extflonum: fix JIT-inlined `extflvector-ref' in 32-bit mode
racket/extflonum: fix JIT-inlined `extflvector-ref' in 32-bit mode

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