Removed the "test:" prefix from locmem template identifiers.

Since it isn't branded as a test utility any more and could be used for
other purposes than test code, that prefix no longer makes sense.

It wasn't used anywhere either.

django/template/loaders/locmem.py

@@ -16,7 +16,6 @@ class Loader(BaseLoader):
     def load_template_source(self, template_name, template_dirs=None,
                              skip_template=None):
         try:
-            return (self.templates_dict[template_name],
-                    "test:%s" % template_name)
+            return self.templates_dict[template_name], template_name
         except KeyError:
             raise TemplateDoesNotExist(template_name)