Merge multiple functions for creating consul containers into one. (#6612)

Merge both functions for creating mongodb containers into one.
Add retries to docker container cleanups.
Require $VAULT_ACC be set to enable AWS tests.

builtin/credential/radius/backend_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/hashicorp/vault/helper/testhelpers/docker"
 	logicaltest "github.com/hashicorp/vault/helper/testhelpers/logical"
 	"github.com/hashicorp/vault/sdk/logical"
 	"github.com/ory/dockertest"
@@ -48,10 +49,7 @@ func prepareRadiusTestContainer(t *testing.T) (func(), string, int) {
 	}
 
 	cleanup := func() {
-		err := pool.Purge(resource)
-		if err != nil {
-			t.Fatalf("Failed to cleanup local container: %s", err)
-		}
+		docker.CleanupResource(t, pool, resource)
 	}
 
 	port, _ := strconv.Atoi(resource.GetPort("1812/udp"))