Problem
-------
In case of MEMORY TABLES, the table content is deleted after every server
restart and to make sure that both master-slave are in sync we log an
implicit DELETE statement in the binary log of the server which just has
restarted.

There are some issues with the above implementation :

I1. DELETE statement is always be written in statement format even if the
    binlog format is ROW.
I2. DELETE statement is always written to the binary log even if
    (super_)read_only is set to 1.

Fix
---

1. To fix I1 we are changing DELETE to TRUNCATE because it is clearly
   mentioned in MYSQL documentation that truncate statement is always written
   in statement format in the binary log.

2. We do not address issue I2, We argue that the violation of read_only
   mode happened already when the table data was erased. The write to the
   binary log is only reflecting that. It should not be expected that
   MEMORY tables obey the rules of read_only. If this induces problems for
   any user, the user should disable the MEMORY engine.

RB#24592