Disallow pending interrupts to be checked during FiberScheduler#unblock #156

Job	Run time
make (zjit-check, --enable-yjit=dev --enable-zjit, 1.85.0)	3m 29s
make (check, --enable-zjit=dev, --zjit-call-threshold=1, -T --zjit-call-threshold=1, --seed=46450)	16m 56s
make (ruby, combo build test, --enable-yjit --enable-zjit)	4m 2s
ZJIT macOS result	4s
	24m 31s

Provide feedback