Introduced two new wsrep_mode options
* REPLICATE_MYISAM
* REPLICATE_ARIA

Depracated wsrep_replicate_myisam parameter and we use
wsrep_mode = REPLICATE_MYISAM instead.

This required small refactoring of wsrep_check_mode_after_open_table
so that both MyISAM and Aria are handled on required DML cases.
Similarly, added Aria to wsrep_should_replicate_ddl to handle DDL
for Aria tables using TOI. Added test cases and improved MyISAM testing.
Changed use of wsrep_replicate_myisam to wsrep_mode = REPLICATE_MYISAM