Bug#25347: mysqlcheck -A -r doesn't repair table marked as crashed

mysqlcheck tests nullness of the engine type to know whether the
"table" is a view or not.  That also falsely catches tables that 
are severly damaged.

Instead, use SHOW FULL TABLES to test whether a "table" is a view
or not.

(Don't add new function.  Instead, get original data a smarter way.)

Make it safe for use against databases before when views appeared.