MDEV-17228 Encrypted temporary tables are not encrypted

- Introduce a new variable called innodb_encrypt_temporary_tables which is
a boolean variable. It decides whether to encrypt the temporary tablespace.
- Encrypts the temporary tablespace based on full checksum format.
- Introduced a new counter to track encrypted and decrypted temporary
tablespace pages.
- Warnings issued if temporary table creation has conflict value with
innodb_encrypt_temporary_tables
- Added a new test case which reads and writes the pages from/to temporary
tablespace.

storage/innobase/srv/srv0srv.cc

@@ -450,6 +450,9 @@ my_bool	srv_print_innodb_lock_monitor;
 PRIMARY KEY */
 my_bool	srv_force_primary_key;
 
+/** Key version to encrypt the temporary tablespace */
+my_bool innodb_encrypt_temporary_tables;
+
 /* Array of English strings describing the current state of an
 i/o handler thread */
 
@@ -1646,6 +1649,12 @@ srv_export_innodb_status(void)
 	export_vars.innodb_n_rowlog_blocks_encrypted = srv_stats.n_rowlog_blocks_encrypted;
 	export_vars.innodb_n_rowlog_blocks_decrypted = srv_stats.n_rowlog_blocks_decrypted;
 
+	export_vars.innodb_n_temp_blocks_encrypted =
+		srv_stats.n_temp_blocks_encrypted;
+
+	export_vars.innodb_n_temp_blocks_decrypted =
+		srv_stats.n_temp_blocks_decrypted;
+
 	export_vars.innodb_defragment_compression_failures =
 		btr_defragment_compression_failures;
 	export_vars.innodb_defragment_failures = btr_defragment_failures;