classes.algebra: update forgotten test for flatten-class.
classes.algebra: update forgotten test for flatten-class.

factor/factor,mrjbq7/factor,AlexIljin/factor,mrjbq7/factor,AlexIljin/factor,tgunr/factor,tgunr/factor,bpollack/factor,tgunr/factor,bpollack/factor,bpollack/factor,AlexIljin/factor,AlexIljin/factor,AlexIljin/factor,factor/factor,AlexIljin/factor,bpollack/factor,tgunr/factor,bpollack/factor,factor/factor,mrjbq7/factor,AlexIljin/factor,factor/factor,bpollack/factor,factor/factor,tgunr/factor,tgunr/factor,bpollack/factor,mrjbq7/factor,mrjbq7/factor,mrjbq7/factor,factor/factor