Merge pull request #6647 from amatsuda/192_minitest_method_name

MiniTest::Spec shipped with Ruby >= 1.9.3 always responds_to __name__

activesupport/lib/active_support/test_case.rb

@@ -22,8 +22,7 @@ class << self
     end
 
     Assertion = MiniTest::Assertion
-    alias_method :method_name, :name if method_defined? :name
-    alias_method :method_name, :__name__ if method_defined? :__name__
+    alias_method :method_name, :__name__
 
     $tags = {}
     def self.for_tag(tag)