Remove a duplicate test of mysql_rake_test

activerecord/test/cases/tasks/mysql_rake_test.rb

@@ -294,13 +294,6 @@ def test_structure_dump
         ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, filename)
       end
 
-      def test_structure_dump
-        filename = "awesome-file.sql"
-        Kernel.expects(:system).with("mysqldump", "--result-file", filename, "--no-data", "--routines", "--skip-comments", "test-db").returns(true)
-
-        ActiveRecord::Tasks::DatabaseTasks.structure_dump(@configuration, filename)
-      end
-
       def test_structure_dump_with_extra_flags
         filename = "awesome-file.sql"
         expected_command = ["mysqldump", "--result-file", filename, "--no-data", "--routines", "--skip-comments", "--noop", "test-db"]