case-folding.rb: modularize

* enc/unicode/case-folding.rb (CaseFolding): modularize, and add
  --output-file option.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46267 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
case-folding.rb: merge tables

* enc/unicode/case-folding.rb (print_table): merge non-locale and
  locale tables, and reduce initializing loops.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46268 b2dd03c8-39d4-4d8f-98ff-823fe69b080e