benchmark.splitting: stop using split* and use slices only.
benchmark.splitting: stop using split* and use slices only.

sarvex/factor-lang,sarvex/factor-lang,slavapestov/factor,dch/factor,factor/factor,bjourne/factor,mrjbq7/factor,AlexIljin/factor,slavapestov/factor,sarvex/factor-lang,bjourne/factor,bpollack/factor,tgunr/factor,mrjbq7/factor,sarvex/factor-lang,sarvex/factor-lang,nicolas-p/factor,factor/factor,nicolas-p/factor,bjourne/factor,dch/factor,sarvex/factor-lang,bpollack/factor,factor/factor,bpollack/factor,tgunr/factor,tgunr/factor,AlexIljin/factor,AlexIljin/factor,AlexIljin/factor,mrjbq7/factor,sarvex/factor-lang,nicolas-p/factor,AlexIljin/factor,dch/factor,slavapestov/factor,bjourne/factor,nicolas-p/factor,nicolas-p/factor,mrjbq7/factor,dch/factor,tgunr/factor,mrjbq7/factor,slavapestov/factor,tgunr/factor,bpollack/factor,bjourne/factor,bpollack/factor,dch/factor,mrjbq7/factor,slavapestov/factor,bjourne/factor,factor/factor,bjourne/factor,AlexIljin/factor,bpollack/factor,AlexIljin/factor,dch/factor,factor/factor,factor/factor,tgunr/factor,nicolas-p/factor,nicolas-p/factor,bpollack/factor,slavapestov/factor,slavapestov/factor