* vm_eval.c (rb_call0): gets rid of checking method cache twice.

* method.h (rb_get_method_entry): added a prototype of the function.
  (rb_method_entry_without_cache): more friendly name.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@24702 b2dd03c8-39d4-4d8f-98ff-823fe69b080e