debug: add utf8-ranges-rev
debug: add utf8-ranges-rev

Because I'm working on optimizing automata construction for Unicode
character classes. It turns out that getting it right for the reverse
direction is a bitch, so this helps visualize it.

rust-lang/regex,rust-lang-nursery/regex,rust-lang-nursery/regex,rust-lang/regex,rust-lang/regex,rust-lang/regex,rust-lang/regex,rust-lang-nursery/regex,rust-lang-nursery/regex,rust-lang-nursery/regex