MDEV-23776: Re-apply the fix and make the test more robust

The test that was added in commit e05650e6
would break a subsequent run of a test encryption.innodb-bad-key-change
because some pages in the system tablespace would be encrypted with
a different key.

The failure was repeatable with the following invocation:

./mtr --no-reorder \
encryption.create_or_replace,cbc \
encryption.innodb-bad-key-change,cbc

Because the crash was unrelated to the code changes that we reverted
in commit eb38b1f7
we can safely re-apply those fixes.

mysql-test/suite/encryption/r/create_or_replace.result

 SET @save_threads = @@GLOBAL.innodb_encryption_threads;
-SET @save_tables = @@GLOBAL.innodb_encrypt_tables;
 SET default_storage_engine = InnoDB;
 SET GLOBAL innodb_encryption_threads = 4;
 CREATE TABLE `table10_int_autoinc` (`col_int_key` int, pk int auto_increment, `col_int` int, key (`col_int_key` ),primary key (pk)) engine=innodb;
@@ -18,4 +17,3 @@ connection default;
 drop table create_or_replace_t, table1_int_autoinc, table0_int_autoinc,
 table10_int_autoinc;
 SET GLOBAL innodb_encryption_threads = @save_threads;
-SET GLOBAL innodb_encrypt_tables = @save_tables;

mysql-test/suite/encryption/t/create_or_replace.opt

+--innodb-encrypt-tables

mysql-test/suite/encryption/t/create_or_replace.test

@@ -3,7 +3,6 @@
 --source include/count_sessions.inc
 
 SET @save_threads = @@GLOBAL.innodb_encryption_threads;
-SET @save_tables = @@GLOBAL.innodb_encrypt_tables;
 
 SET default_storage_engine = InnoDB;
 
@@ -76,5 +75,4 @@ drop table create_or_replace_t, table1_int_autoinc, table0_int_autoinc,
 table10_int_autoinc;
 
 SET GLOBAL innodb_encryption_threads = @save_threads;
-SET GLOBAL innodb_encrypt_tables = @save_tables;
 --source include/wait_until_count_sessions.inc

storage/innobase/fil/fil0crypt.cc

@@ -1483,6 +1483,11 @@ static bool fil_crypt_find_space_to_rotate(
 {
 	/* we need iops to start rotating */
 	while (!state->should_shutdown() && !fil_crypt_alloc_iops(state)) {
+		if (state->space && state->space->is_stopping()) {
+			fil_space_release(state->space);
+			state->space = NULL;
+		}
+
 		os_event_reset(fil_crypt_threads_event);
 		os_event_wait_time(fil_crypt_threads_event, 100000);
 	}
@@ -2506,6 +2511,7 @@ fil_space_crypt_close_tablespace(
 
 		/* wakeup throttle (all) sleepers */
 		os_event_set(fil_crypt_throttle_sleep_event);
+		os_event_set(fil_crypt_threads_event);
 
 		os_thread_sleep(20000);
 		dict_mutex_enter_for_mysql();