assertions.rb: private flag

* lib/test/unit/assertions.rb (assert_respond_to): accept optional
  include-private flag.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39742 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
vm_method.c: overrid flag of prepending method

* vm_method.c (rb_export_method): directly override the flag of method
  defined in prepending class too, not adding zsuper entry.
  [ruby-core:53106] [Bug #8005]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39743 b2dd03c8-39d4-4d8f-98ff-823fe69b080e