test: Disable TestImage.testOSTree{Commit,Container}
test: Disable TestImage.testOSTree{Commit,Container}

These two tests have constantly failed for several months. They cause
blocked VM image refreshes, test timeouts (so that the other tests
often don't run), and block the infra.

jkozol/welder-web,jkozol/welder-web,jkozol/welder-web,jkozol/welder-web