Adding Enumerable#filter_map
Adding Enumerable#filter_map

[Feature #15323]
Closes: https://github.com/ruby/ruby/pull/2017

nobu/rubyspec,ruby/spec,eregon/rubyspec,nobu/rubyspec,nobu/rubyspec,ruby/spec,eregon/rubyspec,ruby/spec,eregon/rubyspec