Description :
=============
In MTR we have *.require files to perform checks. But these require
files are not necessary to perform a check and adds an extra overhead.
Instead of using require files, the check for the condition can be
implemented in corresponding inc files.

E.g:

1) have_debug_sync.inc
----------------------
require r/have_debug_sync.require;
disable_query_log;
let $value=query_get_value(SHOW VARIABLES LIKE 'debug_sync', Value, 1);
eval SELECT ('$value' LIKE 'ON %') AS debug_sync;
enable_query_log;

2) have_debug_sync.require
--------------------------
debug_sync
1

The way this works is that '--require' causes the result of the next
query to be written to a temporary file and then there is a file
comparison of the temporary file and, in this case,
have_debug_sync.require.

This sounds much slower than it could be. And also there are issues on
Windows where a test can fail simply because of line ending differences.

This WL removes all these require files and implements the check in
the corresponding inc file. If '--require' command is used in any of
the test file/inc file, MTR will error out with a deprecation message.

E.g:

Modified have_debug_sync.inc
----------------------------
let $have_debug_sync= query_get_value(SHOW VARIABLES LIKE 'debug_sync', Value, 1);
if ($have_debug_sync == 'No such row')
{
  skip Test requires 'have_debug_sync';
}

Reviewed-by: Anitha Gopi <anitha.gopi@oracle.com>
Reviewed-by: Deepa Dixit <deepa.dixit@oracle.com>
Reviewed-by: Magnus Blåudd <magnus.blaudd@oracle.com>
RB: 14686