Add a test that exercises checkpoint/restore of a process with an
inotify watch on a file inside an overlayfs mount.
The test compiles inotify_test.c (a simple program that sets up an
inotify watch and blocks reading events), starts it watching a file
on an overlay mount, dumps and restores via criu, then verifies the
restored process is still alive.
Run with: make -C test/others/overlayfs run-inotify
Assisted-by: Claude Code (claude-opus-4-6):default
Signed-off-by: Adrian Reber <areber@redhat.com>