tests: Remove the X11 dependency from the EGL tests.

The EGL tests don't use X11, and only included the Xlib headers by way
of eglplatform.h.

Now that we don't set the USE_X11 macro anymore, eglplatform.h won't try
to include anything from Xlib, and so the EGL tests don't need X11 as a
2 jobs for fix-x11-config-option in 2 minutes and 16 seconds (queued for 3 seconds)