variable.c: rb_class_path_cached

* variable.c (rb_class_path_cached): returns cached class path
  only, without searching and allocating new class path string.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44087 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
object_tracing.c: fix allocation from NEWOBJ hook

* ext/objspace/object_tracing.c (newobj_i): use cached class path
  only to get rid object allocation during NEWOBJ hook.
  [ruby-core:58853] [Bug #9212]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44088 b2dd03c8-39d4-4d8f-98ff-823fe69b080e