Renaming a few mysql-test/suite/rpl/include/*.test files into *.inc

Builders:
- amd64-fedora-38-last-N-failed
- amd64-debian-10-last-N-failed
erroneously execute MTR for these files:

- rpl/include/rpl_extra_col_master.test
- rpl/include.rpl_binlog_max_cache_size.test
- rpl/include.rpl_charset.test

when these files are changed by a commit.
Changing their extension from *.test to *.inc to avoid this.

mysql-test/suite/binlog_encryption/rpl_mixed_binlog_max_cache_size.test

@@ -3,5 +3,5 @@
 --source include/not_windows.inc
 --source include/have_binlog_format_mixed.inc
 
---source suite/rpl/include/rpl_binlog_max_cache_size.test
+--source suite/rpl/include/rpl_binlog_max_cache_size.inc
 --source include/rpl_end.inc

mysql-test/suite/rpl/t/rpl_charset.test

@@ -1,2 +1,2 @@
 let $engine_type=myisam;
-source include/rpl_charset.test;
+source include/rpl_charset.inc;

mysql-test/suite/rpl/t/rpl_extra_col_master_innodb.test

@@ -6,6 +6,6 @@
 -- source include/master-slave.inc
 
 let $engine_type = 'InnoDB';
---source include/rpl_extra_col_master.test
+--source include/rpl_extra_col_master.inc
 
 --source include/rpl_end.inc

mysql-test/suite/rpl/t/rpl_extra_col_master_myisam.test

@@ -5,6 +5,6 @@
 -- source include/master-slave.inc
 
 let $engine_type = 'MyISAM';
---source include/rpl_extra_col_master.test
+--source include/rpl_extra_col_master.inc
 
 --source include/rpl_end.inc

mysql-test/suite/rpl/t/rpl_mixed_binlog_max_cache_size.test

@@ -4,5 +4,5 @@
 --source include/have_binlog_format_mixed.inc
 --source include/master-slave.inc
 
---source include/rpl_binlog_max_cache_size.test
+--source include/rpl_binlog_max_cache_size.inc
 --source include/rpl_end.inc

mysql-test/suite/rpl/t/rpl_row_binlog_max_cache_size.test

@@ -4,5 +4,5 @@
 --source include/have_binlog_format_row.inc
 --source include/master-slave.inc
 
---source include/rpl_binlog_max_cache_size.test
+--source include/rpl_binlog_max_cache_size.inc
 --source include/rpl_end.inc

mysql-test/suite/rpl/t/rpl_stm_binlog_max_cache_size.test

@@ -4,5 +4,5 @@
 --source include/have_binlog_format_statement.inc
 --source include/master-slave.inc
 
---source include/rpl_binlog_max_cache_size.test
+--source include/rpl_binlog_max_cache_size.inc
 --source include/rpl_end.inc