Ticket #48226 - In MMR, double free coould occur under some special condition
In a replicated topology, a authenticated user that have write access
on an entry can send a series of operations that crash the server.
The crash is due to an access to a already freed buffer.
To avoid the double free, duplicate a CSNSet and assign it to the
Reviewed by firstname.lastname@example.org (Thank you, Rich!!)
(cherry picked from commit a0f8e0f981a046882db299a7a6d6d1c01bc19571)
(cherry picked from commit bdbc81e62eb8d7b8dfb298c7ba983cf86353fe66)
(cherry picked from commit 413414c98313a076111d8e40a7a10fa369433e6e)