tests: Add ktrace regression test for shm_open

Verify that a capability violation is recorded when shm_open(2) is called
with a non-anonymous path.

Approved by: markj (mentor)
Reviewed by: markj
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D44733

(cherry picked from commit 054a4720591f0c98579bccef2751fd458ee4f71f)