Don't look up s.literals[i] twice
Don't look up s.literals[i] twice

This is worth about 3% in
github.com/julienschmidt/go-http-routing-benchmark's
BenchmarkGoji_GithubAll. Not a huge win, but definitely still worth it.

yangou/goji,unixorn/goji,zenazn/goji,vsco/goji,cognusion/goji,vanackere/slim,beni55/goji,dbmlabs/goji,tchssk/goji,Invacio/goji,w4ngyi/goji