support/testing: test_glxinfo load X11 modules in the right order

From [1]
"Xorg does not implement real dynamic linking and requires that its
modules get loaded in the right order."

From /var/log/Xorg.0.0.log:
 (II) LoadModule: "modesetting"
 (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so
 (EE) Failed to load /usr/lib/xorg/modules/drivers/modesetting_drv.so: /usr/lib/xorg/modules/drivers/modesetting_drv.so: undefined symbol: shadowRemove

Fixes:
https://gitlab.com/buildroot.org/buildroot/-/jobs/1255661899

[1] https://forums.gentoo.org/viewtopic-p-8245578.html#8245578



Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>