Do not include ActiveSupport into test classes

Will help get rid of errors like the following:

```
  1) Error:
JDOMEngineTest#test_order=:
ArgumentError: wrong number of arguments (0 for 1)
    /Users/jon/code/rails/rails/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb:106:in `test_order='
```

activesupport/test/xml_mini/jdom_engine_test.rb

@@ -4,17 +4,15 @@ if RUBY_PLATFORM.include?("java")
   require "active_support/core_ext/hash/conversions"
 
   class JDOMEngineTest < ActiveSupport::TestCase
-    include ActiveSupport
-
     FILES_DIR = File.dirname(__FILE__) + "/../fixtures/xml"
 
     def setup
-      @default_backend = XmlMini.backend
-      XmlMini.backend = "JDOM"
+      @default_backend = ActiveSupport::XmlMini.backend
+      ActiveSupport::XmlMini.backend = "JDOM"
     end
 
     def teardown
-      XmlMini.backend = @default_backend
+      ActiveSupport::XmlMini.backend = @default_backend
     end
 
     def test_file_from_xml
@@ -84,13 +82,13 @@ if RUBY_PLATFORM.include?("java")
     end
 
     def test_setting_JDOM_as_backend
-      XmlMini.backend = "JDOM"
-      assert_equal XmlMini_JDOM, XmlMini.backend
+      ActiveSupport::XmlMini.backend = "JDOM"
+      assert_equal ActiveSupport::XmlMini_JDOM, ActiveSupport::XmlMini.backend
     end
 
     def test_blank_returns_empty_hash
-      assert_equal({}, XmlMini.parse(nil))
-      assert_equal({}, XmlMini.parse(""))
+      assert_equal({}, ActiveSupport::XmlMini.parse(nil))
+      assert_equal({}, ActiveSupport::XmlMini.parse(""))
     end
 
     def test_array_type_makes_an_array
@@ -175,8 +173,8 @@ if RUBY_PLATFORM.include?("java")
 
     private
       def assert_equal_rexml(xml)
-        parsed_xml = XmlMini.parse(xml)
-        hash = XmlMini.with_backend("REXML") { XmlMini.parse(xml) }
+        parsed_xml = ActiveSupport::XmlMini.parse(xml)
+        hash = ActiveSupport::XmlMini.with_backend("REXML") { ActiveSupport::XmlMini.parse(xml) }
         assert_equal(hash, parsed_xml)
       end
   end

activesupport/test/xml_mini/libxml_engine_test.rb

@@ -8,17 +8,15 @@ else
   require "active_support/core_ext/hash/conversions"
 
   class LibxmlEngineTest < ActiveSupport::TestCase
-    include ActiveSupport
-
     def setup
-      @default_backend = XmlMini.backend
-      XmlMini.backend = "LibXML"
+      @default_backend = ActiveSupport::XmlMini.backend
+      ActiveSupport::XmlMini.backend = "LibXML"
 
       LibXML::XML::Error.set_handler(&lambda { |error| }) #silence libxml, exceptions will do
     end
 
     def teardown
-      XmlMini.backend = @default_backend
+      ActiveSupport::XmlMini.backend = @default_backend
     end
 
     def test_exception_thrown_on_expansion_attack
@@ -42,13 +40,13 @@ else
     end
 
     def test_setting_libxml_as_backend
-      XmlMini.backend = "LibXML"
-      assert_equal XmlMini_LibXML, XmlMini.backend
+      ActiveSupport::XmlMini.backend = "LibXML"
+      assert_equal ActiveSupport::XmlMini_LibXML, ActiveSupport::XmlMini.backend
     end
 
     def test_blank_returns_empty_hash
-      assert_equal({}, XmlMini.parse(nil))
-      assert_equal({}, XmlMini.parse(""))
+      assert_equal({}, ActiveSupport::XmlMini.parse(nil))
+      assert_equal({}, ActiveSupport::XmlMini.parse(""))
     end
 
     def test_array_type_makes_an_array
@@ -193,9 +191,9 @@ else
 
     private
       def assert_equal_rexml(xml)
-        parsed_xml = XmlMini.parse(xml)
+        parsed_xml = ActiveSupport::XmlMini.parse(xml)
         xml.rewind if xml.respond_to?(:rewind)
-        hash = XmlMini.with_backend("REXML") { XmlMini.parse(xml) }
+        hash = ActiveSupport::XmlMini.with_backend("REXML") { ActiveSupport::XmlMini.parse(xml) }
         assert_equal(hash, parsed_xml)
       end
   end

activesupport/test/xml_mini/libxmlsax_engine_test.rb

@@ -8,15 +8,13 @@ else
   require "active_support/core_ext/hash/conversions"
 
   class LibXMLSAXEngineTest < ActiveSupport::TestCase
-    include ActiveSupport
-
     def setup
-      @default_backend = XmlMini.backend
-      XmlMini.backend = "LibXMLSAX"
+      @default_backend = ActiveSupport::XmlMini.backend
+      ActiveSupport::XmlMini.backend = "LibXMLSAX"
     end
 
     def teardown
-      XmlMini.backend = @default_backend
+      ActiveSupport::XmlMini.backend = @default_backend
     end
 
     def test_exception_thrown_on_expansion_attack
@@ -42,13 +40,13 @@ else
     end
 
     def test_setting_libxml_as_backend
-      XmlMini.backend = "LibXMLSAX"
-      assert_equal XmlMini_LibXMLSAX, XmlMini.backend
+      ActiveSupport::XmlMini.backend = "LibXMLSAX"
+      assert_equal ActiveSupport::XmlMini_LibXMLSAX, ActiveSupport::XmlMini.backend
     end
 
     def test_blank_returns_empty_hash
-      assert_equal({}, XmlMini.parse(nil))
-      assert_equal({}, XmlMini.parse(""))
+      assert_equal({}, ActiveSupport::XmlMini.parse(nil))
+      assert_equal({}, ActiveSupport::XmlMini.parse(""))
     end
 
     def test_array_type_makes_an_array
@@ -185,9 +183,9 @@ else
 
     private
       def assert_equal_rexml(xml)
-        parsed_xml = XmlMini.parse(xml)
+        parsed_xml = ActiveSupport::XmlMini.parse(xml)
         xml.rewind if xml.respond_to?(:rewind)
-        hash = XmlMini.with_backend("REXML") { XmlMini.parse(xml) }
+        hash = ActiveSupport::XmlMini.with_backend("REXML") { ActiveSupport::XmlMini.parse(xml) }
         assert_equal(hash, parsed_xml)
       end
   end