Make the new merge_alter test indifferent to extra version info

Make the new merge_alter test indifferent to extra version info

Modify the test regex to accept any extra version info, just like it
accepts any server version info. The test is supposed to fail on actual
differences in behaviour and server info strings are intentionally
normalized and not regarded.

Without this modification, the test introduced in 9e8e215e would fail
in post-build MTR on "from Debian-log" and in autopkgtest on "from Debian":

    main.merge_alter                         w4 [ fail ]
            Test ended at 2025-11-26 22:41:38
    CURRENT_TEST: main.merge_alter
    /usr/share/mariadb/mariadb-test/main/merge_alter.result	2025-11-13 11:45:29.000000000 +0300
    /tmp/tmp.3vGjZWHA79/var/4/log/merge_alter.reject	2025-11-27 01:41:38.523996124 +0300
    @@ -10,7 +10,7 @@
     /*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
     DELIMITER /*!*/;
     # at #
    -#010909  4:46:40 server id #  end_log_pos # CRC32 XXX 	Start: binlog v 4, server v #.##.## created 010909  4:46:40 at startup
    +#010909  4:46:40 server id #  end_log_pos # CRC32 XXX 	Start: binlog v 4, server v #.##.## from Debian created 010909  4:46:40 at startup
     ROLLBACK/*!*/;
     # at #
     #010909  4:46:40 server id #  end_log_pos # CRC32 XXX 	Gtid list []
    Result length mismatch

Forwarded: not-needed

Gbp-Pq: Name include-debian-in-test-merge-alter-result.patch