As the logic in bitbake improves, the logic in the tests needs to as well.
Afer we built a task for the first time, allow its setscene hash verification
status to change, mirroring what would happen in a multiconfig build.
(Bitbake rev: 27ec2e69ab3e32972caf8b072b2945736696d83d)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>