maria_chk should fail on all detected corruptions

Now that maria_chk is used for recovery testing, it should have an option to fail with a suitable exit code on all database corruptions. Currently, some are just printed as warnings, such as:

maria_chk: warning: Found row where the auto_increment column has the value 0

and are thus not detectable during automatic test runs. The code has the following comment:

        /* Don't count this as a real warning, as maria_chk can't correct it */

such logic is not true when it comes to automatic recovery testing. There are other instances in the code where the same trick is used to prevent maria_chk from reporting a proper exit code.