RaceNJvmTest has flaky tests

[kyay10]

Specifically, firstRacerOutOf2AlwaysWinsOnASingleThread fails with:

java.lang.AssertionError: Expecting actual not to be null
	at arrow.fx.coroutines.RaceNJvmTest$firstRacerOutOf2AlwaysWinsOnASingleThread$1.invokeSuspend(RaceNJvmTest.kt:73)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.UndispatchedCoroutine.afterResume(CoroutineContext.kt:266)
	at kotlinx.coroutines.AbstractCoroutine.resumeWith(AbstractCoroutine.kt:100)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:46)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:101)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:589)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:832)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:720)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:707)