Fixed buildbot failures with system_mysql_db_fix

mysql-test/r/system_mysql_db_fix40123.result

@@ -287,8 +287,8 @@ column_stats	CREATE TABLE `column_stats` (
   `db_name` varchar(64) COLLATE utf8_bin NOT NULL,
   `table_name` varchar(64) COLLATE utf8_bin NOT NULL,
   `column_name` varchar(64) COLLATE utf8_bin NOT NULL,
-  `min_value` varchar(255) COLLATE utf8_bin DEFAULT NULL,
-  `max_value` varchar(255) COLLATE utf8_bin DEFAULT NULL,
+  `min_value` varbinary(255) DEFAULT NULL,
+  `max_value` varbinary(255) DEFAULT NULL,
   `nulls_ratio` decimal(12,4) DEFAULT NULL,
   `avg_length` decimal(12,4) DEFAULT NULL,
   `avg_frequency` decimal(12,4) DEFAULT NULL,

mysql-test/r/system_mysql_db_fix50030.result

@@ -287,8 +287,8 @@ column_stats	CREATE TABLE `column_stats` (
   `db_name` varchar(64) COLLATE utf8_bin NOT NULL,
   `table_name` varchar(64) COLLATE utf8_bin NOT NULL,
   `column_name` varchar(64) COLLATE utf8_bin NOT NULL,
-  `min_value` varchar(255) COLLATE utf8_bin DEFAULT NULL,
-  `max_value` varchar(255) COLLATE utf8_bin DEFAULT NULL,
+  `min_value` varbinary(255) DEFAULT NULL,
+  `max_value` varbinary(255) DEFAULT NULL,
   `nulls_ratio` decimal(12,4) DEFAULT NULL,
   `avg_length` decimal(12,4) DEFAULT NULL,
   `avg_frequency` decimal(12,4) DEFAULT NULL,

mysql-test/r/system_mysql_db_fix50117.result

@@ -287,8 +287,8 @@ column_stats	CREATE TABLE `column_stats` (
   `db_name` varchar(64) COLLATE utf8_bin NOT NULL,
   `table_name` varchar(64) COLLATE utf8_bin NOT NULL,
   `column_name` varchar(64) COLLATE utf8_bin NOT NULL,
-  `min_value` varchar(255) COLLATE utf8_bin DEFAULT NULL,
-  `max_value` varchar(255) COLLATE utf8_bin DEFAULT NULL,
+  `min_value` varbinary(255) DEFAULT NULL,
+  `max_value` varbinary(255) DEFAULT NULL,
   `nulls_ratio` decimal(12,4) DEFAULT NULL,
   `avg_length` decimal(12,4) DEFAULT NULL,
   `avg_frequency` decimal(12,4) DEFAULT NULL,