Merge pull request #8381 from aderyabin/unnecessary_monkey_patch

Remove outdated monkey patch in mysql tests

activerecord/test/cases/helper.rb

@@ -22,8 +22,6 @@
 # Connect to the database
 ARTest.connect
 
-require 'support/mysql'
-
 # Quote "type" if it's a reserved word for the current connection.
 QUOTED_TYPE = ActiveRecord::Base.connection.quote_column_name('type')
 

activerecord/test/support/mysql.rb

-if defined?(Mysql)
-  class Mysql
-    class Error
-      # This monkey patch fixes annoy warning with mysql-2.8.1.gem when executing testcases.
-      def errno_with_fix_warnings
-        silence_warnings { errno_without_fix_warnings }
-      end
-      alias_method_chain :errno, :fix_warnings
-    end
-  end
-end