More tweeks and bug fixes from unit testing:
*   Renormalise cache & and temp file cleanup to pick up a couple of memory
    leaks and dangling temp file on error paths
*   Add debug random juggle to SMA start to ensure testing of relocation
*   Added some extra DEBUGn diagnostics
*   Fixed a bug in header length calculation
*   Fixed a bug in cache addition integrity check
*   Tweeked Debug ENTRY indentation code
WIP checkpoint. Some changes to debug logging format and preparations for context-driven relocation tagging
WIP version of zend_persist_prepare.c.  I've realise that their is a simpler approach and will refactor this,
so this is just a copy of the old approach for roll-back purposes.