Bug #32628376 BACKPORT FIX OF BUG 32335263 TO 5.6+

PROBLEM
-------
If the query contains password in plain text,
we have the query re-written immediately after
parsing and password string is replaced. However,
there is a unsafe window before rewrite is done
and in such case we should not display the plain
text password.

Affected queries are
SHOW PROCESSLIST;
SELECT ... FROM information_schema.processlist;

Solution:
---------
Fix this is to avoid displaying the
query string till re-write is over.

#rb 26092
#rb 26070

Reviewed-by: Debarun Bannerjee <debarun.bannerjee@oracle.com>
Reviewed-by: Reviewed by: Dyre Tjeldvold <dyre.tjeldvoll@oracle.com>

(cherry picked from commit c7d0c5b6ee1cfc2a5328e9adf058857b43e0a091)