Similar to what is done in Xorg. Not doing this prevented apps from
using GLX with a Composite visual, e.g. Firefox WebRender or Chromium.
v2:
* Fix inverted direct_color test, fixes Chromium as well.
* Drop Composite extension guards, since other Xwayland code calls
compRedirectWindow/compUnredirectWindow unconditionally anyway.
Closes: https://gitlab.freedesktop.org/xorg/xserver/issues/921
Fixes: 8469241592 "xwayland: Add EGL-backed GLX provider"
Reviewed-by: Adam Jackson <ajax@redhat.com> # v1
846e81ecb8