rational.c: add argument type check assertions in f_muldiv
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56724 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
rational.c: add argument type check assertions in f_muldiv
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56724 b2dd03c8-39d4-4d8f-98ff-823fe69b080e