Use Range#{begin,end} instead of Range#{first,last}
Use Range#{begin,end} instead of Range#{first,last}

* Avoid Range#last to follow [Bug#8739](http://bugs.ruby-lang.org/issues/8739)
* Avoid Range#first to adjust style with Range#last

ruby/mspec,kachick/mspec,elia/mspec,kachick/mspec,rubinius/mspec,opal/mspec,opal/mspec,eregon/mspec,ruby/mspec