* proc.c (rb_binding_new_with_cfp): permit to create binding object
  of IFUNC frame.
  When `rb_binding_new_with_cfp()' is called, VM finds out the first
  normal (has iseq) frame and create a binding object of this frame
  and create Env objects. `ep's of related frames are updated
  (`ep's point Env object managed spaces).
  However, `ep' of skipped IFUNC frame was not updated and
  old invalid `ep' was remained. It causes serious problems.
  To solve this issue, permit IFUNC to create binding.
  (Maybe there is no problem on it)
  [ruby-dev:46908] [ruby-trunk - Bug #7774]
* test/ruby/test_settracefunc.rb: add a test.
* vm.c (rb_vm_get_binding_creatable_next_cfp), vm_core.h: added.
* vm_trace.c: fix to use `rb_vm_get_binding_creatable_next_cfp()'.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39067 b2dd03c8-39d4-4d8f-98ff-823fe69b080e