If you're managing your own server you can set the timezone in php.ini by assigning the proper timezone to the date.timezone setting, e.g.:
date.timezone = "Asia/Dubai"
Restart the PHP service afterwards to have it pick up the change.
Alternatively you can set the system timezone on the server (although I'd recommend sticking to the php.ini approach). How you change the system timezone depends on your operating system. On Linux you set/change the symlink /etc/localtime to the desired timezone, e.g.:
ln -sf /usr/share/zoneinfo/Asia/Dubai /etc/localtime
On Windows you change the timezone in the date & time settings.
Again, restart the PHP service to make it pick up the change.
If you don't have admin access to the system you need to set the timezone by adding a line
to your qa-config.php as @esqeudero described in his answer.