test_array.rb: do not assume stable sort

* test/ruby/test_array.rb (test_sort_bang_with_freeze): make a
  clone to copy a <=> singleton method, instead of dup.  which
  element will be called is not predictable.
  [ruby-core:76088] [Bug #12509]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56410 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,10 @@
+Thu Oct 13 00:39:08 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* test/ruby/test_array.rb (test_sort_bang_with_freeze): make a
+	  clone to copy a <=> singleton method, instead of dup.  which
+	  element will be called is not predictable.
+	  [ruby-core:76088] [Bug #12509]
+
 Thu Oct 13 00:21:27 2016  Simon Soriano  <simon0191@gmail.com>
 
 	* doc/extension.rdoc: Replace "You can defined hooked variables"

test/ruby/test_array.rb

@@ -1488,7 +1488,7 @@ class TestArray < Test::Unit::TestCase
         1
       }
     }
-    o2 = o1.dup
+    o2 = o1.clone
     ary << o1 << o2
     orig = ary.dup
     assert_raise(RuntimeError, "frozen during comparison") {ary.sort!}