Instead of sending every little rect. Lets x11perf run to completion,
makes 'while true; do gtkperf -a; done' take longer to crash.
This is effectively a resend of the same logic against the old
xfree86+xwayland branch:
http://lists.x.org/archives/xorg-devel/2013-October/038453.html
Reviewed-by: Daniel Stone <daniel@fooishbar.org>
Reviewed-by: Kristian Høgsberg <krh@bitplanet.net>
Signed-off-by: Adam Jackson <ajax@redhat.com>