fix a test
fix a test

Using `racket` now creates a will executor via `ffi/unsafe`, which
interferes with the test's expected count, while using `racket/base`
doesn't.

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