Ruby

• benchmark/bm_vm1_yield.rb: add a benchmark to measure `yield'
  (invoke empty block) performance.
• benchmark/bm_vm2_method_with_block.rb: add a benchmark to measure
  method invocation with empty block.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37230 b2dd03c8-39d4-4d8f-98ff-823fe69b080e