Add stateless security group test case

It's a simple test case that creates, updates a stateless SG and
checks that the attribute is updated accordingly.

Related-Bug: #1949451
Depends-On: I85f7749e7e6186b9e3a7534bce6c306b18702333
Change-Id: I30e0a11c45618cbdaa0130942cb67ea99bbd0b92
2 files changed