Fetch the raw 'Template' header in the WP_Theme constructor. By passing...

Fetch the raw 'Template' header in the WP_Theme constructor. By passing sanitization routines (which are unnecessary for this header), we prevent a persistent themes cache from sanitizing the headers of every theme until/unless they actually need a real header like Name. Note that if WP_Theme was instantiated through get_themes(), this will have no effect, as get_themes() does ask for Name for the keys to return. see #20103.

git-svn-id: https://core.svn.wordpress.org/trunk@20132 1a063a9b-81f0-0310-95a4-ce76da25c4cd