[1.2.X] Modified the egg template loader tests; firstly to ensure that we are...

[1.2.X] Modified the egg template loader tests; firstly to ensure that we are testing the new, non-deprecated interface; secondly to ensure that the old deprecated interface is also tested, but deprecation warnings are silenced.

Backport of r13812 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@13813 bcc190cf-cafb-0310-a4f2-bffc1f526a37