image: skip the import test on AArch64

The commit '0a13f827a10d3bf61744d9b3f7165c5885a39c5d' introduces an
import test for CVE-2017-14992, it uses a 8GB image to make sure we
don't revert CVE-2017-14992, but unfortunately this test can't finish
in 5-min on AArch64, as a fact, in most cases we have to crate a very
big image to make the test effective on AArch64, but this will result
in a test panic, so now we skip it order to avoid termination of others
tests followed.

Signed-off-by: Dennis Chen <dennis.chen@arm.com>

integration/image/import_test.go

@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"context"
 	"io"
+	"runtime"
 	"testing"
 
 	"github.com/docker/docker/api/types"
@@ -14,12 +15,17 @@ import (
 
 // Ensure we don't regress on CVE-2017-14992.
 func TestImportExtremelyLargeImageWorks(t *testing.T) {
+	if runtime.GOARCH == "arm64" {
+		t.Skip("effective test will be time out")
+	}
+
 	client := request.NewAPIClient(t)
 
 	// Construct an empty tar archive with about 8GB of junk padding at the
 	// end. This should not cause any crashes (the padding should be mostly
 	// ignored).
 	var tarBuffer bytes.Buffer
+
 	tw := tar.NewWriter(&tarBuffer)
 	if err := tw.Close(); err != nil {
 		t.Fatal(err)