Use proper ctor for standalone mocks

This removes the 'createSpecial' and 'destroySpecial' static functions
and replaces them wiht proper constructors.

Change-Id: I7c558ac039311001fd7a4842f8ce90f7a83d1565
Reviewed-on: http://review.couchbase.org/34155
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>