* array.c (rb_ary_shuffle_bang, rb_ary_sample): check
  unknown keywords.

* test/ruby/test_array.rb (test_shuffle, test_sample): tests for
  the above.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44064 b2dd03c8-39d4-4d8f-98ff-823fe69b080e