test_thread.rb: assert_operator for comparison

* test/ruby/test_thread.rb (test_priority): use assert_operator
  for comparison instead of assert_send.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44215 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_thread.rb

@@ -140,7 +140,7 @@ class TestThread < Test::Unit::TestCase
     end
     t1.kill
     t2.kill
-    assert_send([c1, :>, c2], "[ruby-dev:33124]") # not guaranteed
+    assert_operator(c1, :>, c2, "[ruby-dev:33124]") # not guaranteed
   end
 
   def test_new