`race-until` test runs forever (1.2.0 + affinity patch, NetBSD 9 amd64) about fibers

[gdt]

Actually some take longer but are clearly not stuck:

assert terminates: (run-fibers (lambda () (spawn-fiber-tree 5 (lambda () (sleep 1)))) #:drain? #t): ok (1.011651015 s)
assert terminates: (run-fibers (lambda () (spawn-fiber-chain 5)) #:drain? #t): ok (9.70913e-4 s)
assert terminates: (run-fibers (lambda () (spawn-fiber-chain 50)) #:drain? #t): ok (0.001394422 s)
assert terminates: (run-fibers (lambda () (spawn-fiber-chain 500)) #:drain? #t): ok (0.007145873 s)
assert terminates: (run-fibers (lambda () (spawn-fiber-chain 5000)) #:drain? #t): ok (0.05655267 s)
assert terminates: (run-fibers (lambda () (spawn-fiber-chain 50000)) #:drain? #t): ok (0.591639325 s)
assert terminates: (run-fibers (lambda () (spawn-fiber-chain 500000)) #:drain? #t): ok (5.526817611 s)
assert terminates: (run-fibers (lambda () (spawn-fiber-chain 5000000)) #:drain? #t): ok (55.836063731 s)
assert terminates: (run-fibers (lambda () (test-run-order 10)) #:parallelism 1 #:drain? #t): ok (0.038900581 s)
assert terminates: (run-fibers (lambda () (test-wakeup-order 10)) #:parallelism 1 #:drain? #t): ok (2.51773e-4 s)
assert terminates: (run-fibers (lambda () 1) #:drain? #t): ok (7.68028e-4 s)
assert run-fiber-return-vals equal to (1): ok
assert terminates: (run-fibers (lambda () (do-times 20 (check-sleep (random 1.0)))) #:drain? #t): assert sleep 0.06564007283307066s < actual 0.071227626s: #t (diff: 8.512411589089872%)