[18.09 backport] integration-cli: Skip TestAPIImagesSaveAndLoad on RS3 and older

[thaJeztah]

backport of moby#39910
addresses moby#39909

I've seen this test fail a number of times recently on RS1

Looking at failures, the test is taking a long time ro run (491.77s, which is
more than 8 minutes), so perhaps it's just too slow on RS1, which may be
because we switch to a different base image, or because we're now running
on different machines.

Compared to RS5 (still slow, but a lot faster);

--- PASS: Test/DockerSuite/TestAPIImagesSaveAndLoad (146.25s)

 --- FAIL: Test/DockerSuite/TestAPIImagesSaveAndLoad (491.77s)
     cli.go:45: assertion failed:
         Command:  d:\CI-5\CI-93d2cf881\binary\docker.exe inspect --format {{.Id}} sha256:69e7c1ff23be5648c494294a3808c0ea3f78616fad67bfe3b10d3a7e2be5ff02
         ExitCode: 1
         Error:    exit status 1
         Stdout:

         Stderr:   Error: No such object: sha256:69e7c1ff23be5648c494294a3808c0ea3f78616fad67bfe3b10d3a7e2be5ff02

         Failures:
         ExitCode was 1 expected 0
         Expected no error

[thaJeztah]

Failure is unrelated; https://ci.docker.com/public/job/engine/job/PR-394/2/execution/node/184/log/?consoleFull

tracked through moby#34988, and should be fixed by moby#39531, which is being backported to this branch in #346

00:30:43.907  FAIL: docker_api_swarm_test.go:362: DockerSwarmSuite.TestAPISwarmRaftQuorum
00:30:43.907  
00:30:43.907  Creating a new daemon at: /go/src/github.com/docker/docker/bundles/test-integration/3/DockerSwarmSuite.TestAPISwarmRaftQuorum
00:30:43.907  [dfe5d618d72da] waiting for daemon to start
00:30:43.907  [dfe5d618d72da] daemon started
00:30:43.907  
00:30:43.907  Creating a new daemon at: /go/src/github.com/docker/docker/bundles/test-integration/3/DockerSwarmSuite.TestAPISwarmRaftQuorum
00:30:43.907  [dcc703fba9000] waiting for daemon to start
00:30:43.907  [dcc703fba9000] daemon started
00:30:43.907  
00:30:43.907  Creating a new daemon at: /go/src/github.com/docker/docker/bundles/test-integration/3/DockerSwarmSuite.TestAPISwarmRaftQuorum
00:30:43.907  [d20a1df24b30c] waiting for daemon to start
00:30:43.907  [d20a1df24b30c] daemon started
00:30:43.907  
00:30:43.907  [dcc703fba9000] exiting daemon
00:30:43.907  waited for 146.805107ms (out of 30s)
00:30:43.907  [d20a1df24b30c] exiting daemon
00:30:43.907  docker_api_swarm_test.go:394:
00:30:43.907      // d1 will eventually step down from leader because there is no longer an active quorum, wait for that to happen
00:30:43.907      waitAndAssert(c, defaultReconciliationTimeout, func(c *check.C) (interface{}, check.CommentInterface) {
00:30:43.907          _, err := cli.ServiceCreate(context.Background(), service.Spec, types.ServiceCreateOptions{})
00:30:43.907          return err.Error(), nil
00:30:43.907      }, checker.Contains, "Make sure more than half of the managers are online.")
00:30:43.907  docker_utils_test.go:435:
00:30:43.907      c.Assert(v, checker, args...)
00:30:43.907  ... obtained string = "Error response from daemon: rpc error: code = DeadlineExceeded desc = context deadline exceeded"
00:30:43.907  ... substring string = "Make sure more than half of the managers are online."
00:30:43.907  
00:30:43.907  waited for 34.337970442s (out of 30s)

[andrewhsu]

LGTM