MDEV-20306 Assert when converting encrypted Aria table to S3

Changes:
- maria_create() now uses a bit in the parameter flags to check if table
  should be encrypted instead of using maria_encrypted_tables.
- Don't encrypt tables that are to be converted to S3
- Added encrypted flag to ARIA_TABLE_CAPABILITIES
- maria_chk --description now prints if table is encrypted. Other
  operations is not allowed on encrypted tables.

mysql-test/suite/s3/encryption.test

@@ -0,0 +1,36 @@
+--source include/have_s3.inc
+
+if (`SELECT COUNT(*)=0 FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME = 'file_key_management' AND PLUGIN_STATUS='ACTIVE'`)
+{
+  --skip Test requires file_key_management plugin
+}
+
+#
+# Create unique database for running the tests
+#
+--source create_database.inc
+
+--echo #
+--echo # MDEV-20306
+--echo # Assertion `!(end_of_data > info->scan.dir_end)' failed in
+--echo # _ma_scan_block_record upon converting table from S3 to Aria
+--echo # with encryption enabled
+--echo #
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
+CREATE TABLE t1 (a INT) ENGINE=Aria;
+INSERT INTO t1 VALUES (1);
+ALTER TABLE t1 ENGINE=S3;
+select * from t1;
+show create table t1;
+ALTER TABLE t1 ENGINE=Aria;
+select * from t1;
+DROP TABLE t1;
+
+#
+# clean up
+#
+--source drop_database.inc