* benchmark/gc/gcbench.rb: print HWM (high water mark) if possible.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43495 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2013-11-01

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43496 b2dd03c8-39d4-4d8f-98ff-823fe69b080e