Sleep for 1.5 seconds before looking at the resize error

This test is very flaky, the retry loop runs for 550ms and some more, 750ms is
cleary not enough for everything to set and for the cli to return the tty resize
error. A sleep of 1.5 seconds in this test should be enough for the retry loop to
finish.

Signed-off-by: Djordje Lukic <djordje.lukic@docker.com>

cli/command/container/tty_test.go

@@ -25,6 +25,6 @@ func TestInitTtySizeErrors(t *testing.T) {
 	ctx := context.Background()
 	cli := test.NewFakeCli(&fakeClient{containerExecResizeFunc: fakeContainerExecResizeFunc})
 	initTtySize(ctx, cli, "8mm8nn8tt8bb", true, fakeResizeTtyFunc)
-	time.Sleep(750 * time.Millisecond)
+	time.Sleep(1500 * time.Millisecond)
 	assert.Check(t, is.Equal(expectedError, cli.ErrBuffer().String()))
 }