Ruby

compile.c: optimization of defined? in condition

• compile.c (compile_branch_condition): trivial optimization of
  defined? expression in a branch condition, where a string is not
  needed, but just a boolean.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57381 b2dd03c8-39d4-4d8f-98ff-823fe69b080e