- Removed unused define CR_INVALID_CONN_HANDLE which was removed entirely in more modern MariaDB versions
(cherry picked from commit 2a7a1b27d59d26d48e958c64f2a05b58fa7434c1)
* Prevents double deletion of MySQLConnection after errors
* The object stays valid after an error and will wait for a reconnect
* Also crash the server if 5 reconnects fail
* Corrects an issue where the server was crashed after one reconnect
because mysql_thread_id was invoked with an invalid handle
(cherry picked from commit 62815c6e1c0427e1d0229d02b1ba70449654cded)