Move test helpers into test_helpers (rails#54688)

Author: dwightwatson

railties/lib/rails/generators/rails/authentication/authentication_generator.rb

@@ -31,7 +31,7 @@ def create_authentication_files
         template "app/views/passwords_mailer/reset.text.erb"
 
         template "test/mailers/previews/passwords_mailer_preview.rb"
-        template "test/helpers/session_test_helper.rb"
+        template "test/test_helpers/session_test_helper.rb"
       end
 
       def configure_application_controller
@@ -58,7 +58,7 @@ def add_migrations
       end
 
       def configure_test_helper
-        inject_into_file "test/test_helper.rb", "require_relative \"helpers/session_test_helper\"\n", after: "require \"rails/test_help\"\n"
+        inject_into_file "test/test_helper.rb", "require_relative \"test_helpers/session_test_helper\"\n", after: "require \"rails/test_help\"\n"
         inject_into_class "test/test_helper.rb", "TestCase", "    include SessionTestHelper\n"
       end