Cleanup test sys_vars.innodb_buffer_pool_size_basic

When using huge pages, the innodb_buffer_pool_size cannot necessarily
be restored. Simplify things by restarting the server.

mysql-test/suite/sys_vars/r/innodb_buffer_pool_size_basic.result

@@ -50,5 +50,3 @@ COUNT(@@GLOBAL.innodb_buffer_pool_size)
 1 Expected
 SELECT innodb_buffer_pool_size = @@SESSION.innodb_buffer_pool_size;
 ERROR 42S22: Unknown column 'innodb_buffer_pool_size' in 'field list'
-Expected error 'Readonly variable'
-SET @@GLOBAL.innodb_buffer_pool_size = @start_buffer_pool_size;

mysql-test/suite/sys_vars/t/innodb_buffer_pool_size_basic.test

@@ -27,7 +27,6 @@
 --disable_query_log
 if (`select (version() like '%debug%') > 0`)
 {
-    set @old_innodb_disable_resize = @@innodb_disable_resize_buffer_pool_debug;
     set global innodb_disable_resize_buffer_pool_debug = OFF;
 }
 --enable_query_log
@@ -116,15 +115,7 @@ SELECT COUNT(@@GLOBAL.innodb_buffer_pool_size);
 
 --Error ER_BAD_FIELD_ERROR
 SELECT innodb_buffer_pool_size = @@SESSION.innodb_buffer_pool_size;
---echo Expected error 'Readonly variable'
 
 
-SET @@GLOBAL.innodb_buffer_pool_size = @start_buffer_pool_size;
---source include/wait_condition.inc
-
---disable_query_log
-if (`select (version() like '%debug%') > 0`)
-{
-    set global innodb_disable_resize_buffer_pool_debug = @old_innodb_disable_resize;
-}
---enable_query_log
+# Restore the original buffer pool size.
+--source include/restart_mysqld.inc