Update go fuzz to directly instantiate server

Avoid importing the cmd libraries and create the server instance
directly from the server library.

Signed-off-by: Derek McGowan <derek@mcg.dev>

contrib/fuzz/containerd_import_fuzzer.go

@@ -22,16 +22,9 @@ import (
 	fuzz "github.com/AdaLogics/go-fuzz-headers"
 
 	"github.com/containerd/containerd"
-	_ "github.com/containerd/containerd/cmd/containerd/builtins"
 	"github.com/containerd/containerd/namespaces"
 )
 
-const (
-	defaultRoot    = "/var/lib/containerd"
-	defaultState   = "/tmp/containerd"
-	defaultAddress = "/tmp/containerd/containerd.sock"
-)
-
 func fuzzContext() (context.Context, context.CancelFunc) {
 	ctx, cancel := context.WithCancel(context.Background())
 	ctx = namespaces.WithNamespace(ctx, "fuzzing-namespace")