merge revision(s) 40583,40584,40585,40590: [Backport #8367]

	* insns.def (defined): get method entry from the method top level
	  frame, not block frame.  [ruby-core:54769] [Bug #8367]

	* insns.def (defined): use vm_search_superclass() like as normal super
	  call.  based on a patch <https://gist.github.com/wanabe/5520026> by
	  wanabe.

	* vm_insnhelper.c (vm_search_superclass): return error but not raise
	  exceptions.

	* vm_insnhelper.c (vm_search_super_method): check the result of
	  vm_search_superclass and raise execptions on error.
	  vm_search_superclass and raise exceptions on error.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@40613 b2dd03c8-39d4-4d8f-98ff-823fe69b080e