ci: drop xorg + weston workaround now that no user is left

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36559>

.gitlab-ci/common/init-stage2.sh

@@ -166,6 +166,11 @@ fi
 ARCH=$(uname -m)
 export VK_DRIVER_FILES="/install/share/vulkan/icd.d/${VK_DRIVER}_icd.$ARCH.json"
 
+if [ -n "$HWCI_START_WESTON" ] && [ -n "$HWCI_START_XORG" ]; then
+  echo "Please drop HWCI_START_XORG and instead use Weston XWayland for testing."
+  exit 1
+fi
+
 # If we want Xorg to be running for the test, then we start it up before the
 # HWCI_TEST_SCRIPT because we need to use xinit to start X (otherwise
 # without using -displayfd you can race with Xorg's startup), but xinit will eat
@@ -187,12 +192,6 @@ if [ -n "$HWCI_START_XORG" ]; then
 fi
 
 if [ -n "$HWCI_START_WESTON" ]; then
-  if [ -n "$HWCI_START_XORG" ]; then
-    echo "Please consider dropping HWCI_START_XORG and instead using Weston XWayland for testing."
-    # shellcheck disable=2034
-    WESTON_X11_SOCK="/tmp/.X11-unix/X1"
-  fi
-
   . /install/common/weston.sh --renderer=gl
   BACKGROUND_PIDS="$! $BACKGROUND_PIDS"
 fi

.gitlab-ci/common/weston.sh

@@ -2,8 +2,6 @@
 
 CI_COMMON_DIR=$(dirname -- "${BASH_SOURCE[0]}")
 
-# init-stage2.sh overwrites this when xorg is already started
-WESTON_X11_SOCK=${WESTON_X11_SOCK:-/tmp/.X11-unix/X0}
 mkdir -p /tmp/.X11-unix
 export DISPLAY=:0
 
@@ -11,4 +9,4 @@ WAYLAND_DISPLAY=wayland-0
 weston --config="$CI_COMMON_DIR/weston.ini" --socket="$WAYLAND_DISPLAY" "$@" &
 export WAYLAND_DISPLAY
 
-while [ ! -S "$WESTON_X11_SOCK" ]; do sleep 1; done
+while [ ! -S /tmp/.X11-unix/X0 ]; do sleep 1; done