Make encryption.innodb_lotoftables more robust.

Perform a slow shutdown at the start of the test, and create all
InnoDB tables with STATS_PERSISTENT=0, so that any I/O related to
background tasks (change buffer merge, purge, persistent statistics)
should be eliminated.

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

+SET GLOBAL innodb_fast_shutdown=0;
 SET GLOBAL innodb_file_format = `Barracuda`;
 SET GLOBAL innodb_file_per_table = ON;
 SHOW VARIABLES LIKE 'innodb_encrypt%';
@@ -11,13 +12,13 @@ create database innodb_encrypted_1;
 use innodb_encrypted_1;
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	3
+Innodb_pages0_read	1
 set autocommit=0;
 set autocommit=1;
 commit work;
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	3
+Innodb_pages0_read	1
 # should be 100
 SELECT COUNT(*) FROM INFORMATION_SCHEMA.INNODB_TABLESPACES_ENCRYPTION WHERE NAME LIKE 'innodb_encrypted%';
 COUNT(*)
@@ -87,47 +88,47 @@ Innodb_pages0_read	3
 # Restart Success!
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	3
+Innodb_pages0_read	1
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	3
+Innodb_pages0_read	1
 use test;
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	3
+Innodb_pages0_read	1
 use innodb_encrypted_1;
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	3
+Innodb_pages0_read	1
 use innodb_encrypted_2;
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	3
+Innodb_pages0_read	1
 use innodb_encrypted_3;
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	3
+Innodb_pages0_read	1
 use innodb_encrypted_1;
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	3
+Innodb_pages0_read	1
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	103
+Innodb_pages0_read	101
 use innodb_encrypted_2;
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	103
+Innodb_pages0_read	101
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	203
+Innodb_pages0_read	201
 use innodb_encrypted_3;
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	203
+Innodb_pages0_read	201
 show status like 'innodb_pages0_read%';
 Variable_name	Value
-Innodb_pages0_read	303
+Innodb_pages0_read	301
 SELECT COUNT(*) FROM INFORMATION_SCHEMA.INNODB_TABLESPACES_ENCRYPTION WHERE MIN_KEY_VERSION = 0 AND NAME LIKE 'innodb_encrypted%';
 COUNT(*)
 100

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

@@ -11,6 +11,10 @@ let $innodb_file_per_table_orig = `SELECT @@innodb_file_per_table`;
 let $innodb_encryption_threads_orig = `SELECT @@global.innodb_encryption_threads`;
 --enable_query_log
 
+# empty the change buffer and the undo logs to avoid extra reads
+SET GLOBAL innodb_fast_shutdown=0;
+--source include/restart_mysqld.inc
+
 SET GLOBAL innodb_file_format = `Barracuda`;
 SET GLOBAL innodb_file_per_table = ON;
 
@@ -29,7 +33,8 @@ let $tables = 100;
 --disable_query_log
 while ($tables)
 {
-  eval create table t_$tables (a int not null primary key, b varchar(200)) engine=innodb;
+  eval create table t_$tables (a int not null primary key, b varchar(200)) engine=innodb
+  stats_persistent=0;
   commit;
   let $rows = 100;
   while($rows)
@@ -64,7 +69,8 @@ set autocommit=0;
 let $tables = 100;
 while ($tables)
 {
-  eval create table t_$tables (a int not null primary key, b varchar(200)) engine=innodb encrypted=yes;
+  eval create table t_$tables (a int not null primary key, b varchar(200)) engine=innodb
+  stats_persistent=0 encrypted=yes;
   commit;
   let $rows = 100;
   while($rows)
@@ -100,7 +106,8 @@ set autocommit=0;
 let $tables = 100;
 while ($tables)
 {
-  eval create table t_$tables (a int not null primary key, b varchar(200)) engine=innodb encrypted=no;
+  eval create table t_$tables (a int not null primary key, b varchar(200)) engine=innodb
+  stats_persistent=0 encrypted=no;
   commit;
   let $rows = 100;
   while($rows)