server/tests: test_display_streaming - test wide sized frames
server/tests: test_display_streaming - test wide sized frames

Before, we tested only higher frames, while wider frames would have
triggered a bug in mjpeg_encoder, when spice is linked with libjpeg and
not libjpeg-turbo.

elmarco/spice,freedesktop-unofficial-mirror/spice__spice,Fantu/spice,mathslinux/spice,fgouget/spice,dezelin/spice,alon/spice-server,freedesktop-unofficial-mirror/spice__spice,ya-mouse/spice,elmarco/spice,mathslinux/spice,fgouget/spice,dezelin/spice,elmarco/spice,alon/spice-server,freedesktop-unofficial-mirror/spice__spice,freedesktop-unofficial-mirror/spice__spice,alon/spice-server,ya-mouse/spice,fgouget/spice,SPICE/spice,mathslinux/spice,ya-mouse/spice,freedesktop-unofficial-mirror/spice__spice,mathslinux/spice,fgouget/spice,dezelin/spice,Fantu/spice,mathslinux/spice,alon/spice-server,elmarco/spice,dezelin/spice,SPICE/spice,alon/spice-server,dezelin/spice,SPICE/spice,elmarco/spice,Fantu/spice,Fantu/spice