Adding tests to CacheHelper
Fixing CacheHelper not parsing cake:nocache after $content_for_layout when view file has cake:nocache tags as well.
Closes#5275
git-svn-id: https://svn.cakephp.org/repo/branches/1.2.x.x@7560 3807eeeb-6ff5-0310-8944-8be069107fe0