MDEV-19632 Replication aborts with ER_SLAVE_CONVERSION_FAILED upon CREATE ... SELECT in ORACLE mode

- Adding optional qualifiers to data types:
    CREATE TABLE t1 (a schema.DATE);
  Qualifiers now work only for three pre-defined schemas:

    mariadb_schema
    oracle_schema
    maxdb_schema

  These schemas are virtual (hard-coded) for now, but may turn into real
  databases on disk in the future.

- mariadb_schema.TYPE now always resolves to a true MariaDB data
  type TYPE without sql_mode specific translations.

- oracle_schema.DATE translates to MariaDB DATETIME.

- maxdb_schema.TIMESTAMP translates to MariaDB DATETIME.

- Fixing SHOW CREATE TABLE to use a qualifier for a data type TYPE
  if the current sql_mode translates TYPE to something else.

The above changes fix the reported problem, so this script:

    SET sql_mode=ORACLE;
    CREATE TABLE t2 AS SELECT mariadb_date_column FROM t1;

is now replicated as:

    SET sql_mode=ORACLE;
    CREATE TABLE t2 (mariadb_date_column mariadb_schema.DATE);

and the slave can unambiguously treat DATE as the true MariaDB DATE
without ORACLE specific translation to DATETIME.

Similar,

    SET sql_mode=MAXDB;
    CREATE TABLE t2 AS SELECT mariadb_timestamp_column FROM t1;

is now replicated as:

    SET sql_mode=MAXDB;
    CREATE TABLE t2 (mariadb_timestamp_column mariadb_schema.TIMESTAMP);

so the slave treats TIMESTAMP as the true MariaDB TIMESTAMP
without MAXDB specific translation to DATETIME.

mysql-test/mysql-test-run.pl

@@ -179,6 +179,7 @@ my @DEFAULT_SUITES= qw(
     binlog_encryption-
     csv-
     compat/oracle-
+    compat/maxdb-
     encryption-
     federated-
     funcs_1-