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.


client/mysqlcheck.c:
  Use SHOW FULL TABLES to test better whether a name in the table
  list is one of a view.  Checking that the engine is NULL is 
  insufficient.
  
  Implemented suggestion from jimw that involved removing most of 
  original patch and getting data a better way
mysql-test/r/mysqlcheck.result:
  Verify that tables that have NULL/unreadable engine types are 
  processed and not interpreted as views.
mysql-test/t/mysqlcheck.test:
  Verify that tables that have NULL/unreadable engine types are 
  processed and not interpreted as views.