The problem is that one can not create a stored routine if sql_mode
contains NO_ENGINE_SUBSTITUTION or PAD_CHAR_TO_FULL_LENGTH. Also when
a event is created, the mode is silently lost if sql_mode contains one
of the aforementioned.  This was happening because the table definitions
which stored sql_mode values weren't being updated to accept new values
of sql_mode.

The solution is to update, in a backwards compatible manner, the various
table definitions (columns) that store the sql_mode value to take into
account the new possible values. One incompatible change is that if a event
that is being created can't be stored to the mysql.event table, an error
will be raised.

The tests case also ensure that new SQL modes will be added to the mysql.proc
and mysql.event tables, otherwise the tests will fail.