Thread#to_s is not same as #inspect on old version.
Thread#to_s is not same as #inspect on old version.

Thread#to_s returns simple Object#to_s until Ruby 2.4.

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