xf86-video-intel: disable non-deterministic tests for libX11

xf86-video-intel: disable non-deterministic tests for libX11

libX11 et al are checked for at confgure time and tests optionally built.  As
these don't get installed we don't want to add build dependencies, but the
non-determinism means that builds can fail.

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>