ci: Run tests inside Crosvm

Allow running tests within Crosvm for testing the virtio-gpu winsys in
Virgl, tested with Piglit only for now.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10862>

.gitlab-ci/crosvm-init.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+set -ex
+
+mount -t proc none /proc
+mount -t sysfs none /sys
+mount -t devtmpfs none /dev || echo possibly already mounted
+mkdir -p /dev/pts
+mount -t devpts devpts /dev/pts
+mount -t tmpfs tmpfs /tmp
+
+. /crosvm-env.sh
+
+# / is ro
+export PIGLIT_REPLAY_EXTRA_ARGS="$PIGLIT_REPLAY_EXTRA_ARGS --db-path /tmp/replayer-db"
+
+if sh $CROSVM_TEST_SCRIPT; then
+    touch /results/success
+fi
+
+poweroff -d -n -f || true
+
+sleep 10   # Just in case init would exit before the kernel shuts down the VM
+
+exit 1