jenkins: add a script to execute tests on overlayfs

Here are all tests which pass now

And I created an issue to investigate fails of other tests:
https://github.com/xemul/criu/issues/136Signed-off-by: Andrew Vagin <avagin@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

test/jenkins/criu-overlay.sh

+# Make one regular C/R cycle
+set -e
+source `dirname $0`/criu-lib.sh
+prep
+mkdir -p test.up test.work
+mount -t overlay overlay -olowerdir=test,upperdir=test.up,workdir=test.work test
+./test/zdtm.py run --all --report report --parallel 4 -x inotify -x mntns_open -x socket -x sk-unix -x unlink -x fsnotify -x fanotify -x ghost || fail