The problem is that creating a event could fail if the value of
the variable server_id didn't fit in the originator column of
the event system table. The cause is two-fold: it was possible
to set server_id to a value outside the documented range (from
0 to 2^32-1) and the originator column of the event table didn't
have enough room for values in this range.

The log tables (general_log and slow_log) also don't have a proper
column type to store the server_id and having a large server_id
value could prevent queries from being logged.

The solution is to ensure that all system tables that store the
server_id value have a proper column type (int unsigned) and that
the variable can't be set to a value that is not within the range.

mysql-test/r/events_bugs.result:
  Add test case result for Bug#36540
mysql-test/r/log_tables.result:
  Update column type.
mysql-test/r/system_mysql_db.result:
  Update column type.
mysql-test/r/variables.result:
  Add test case result for server_id value range.
mysql-test/suite/sys_vars/r/server_id_basic_64.result:
  Update test case results.
mysql-test/t/events_bugs.test:
  Add test case for Bug#36540
mysql-test/t/log_tables.test:
  Fix column type.
mysql-test/t/variables.test:
  Add test case for server_id value range.
scripts/mysql_system_tables.sql:
  Columns that store the server_id value must be of type INT UNSIGNED,
  fix event (originator), general_log and slow_log (server_id) tables
  in accordance.
scripts/mysql_system_tables_fix.sql:
  Columns that store the server_id value must be of type INT UNSIGNED,
  fix event (originator), general_log and slow_log (server_id) tables
  in accordance.
sql/mysqld.cc:
  Set min and max values for the server_id variable.
  Unfortunately we can't easily change server_id variable type
  from ulong to uint32 because of the sys_var classes.