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/builtins_linux.go

@@ -0,0 +1,27 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package fuzz
+
+import (
+	// Linux specific imports
+	_ "github.com/containerd/containerd/metrics/cgroups"
+	_ "github.com/containerd/containerd/metrics/cgroups/v2"
+	_ "github.com/containerd/containerd/runtime/v2/runc/options"
+	_ "github.com/containerd/containerd/snapshots/blockfile/plugin"
+	_ "github.com/containerd/containerd/snapshots/native/plugin"
+	_ "github.com/containerd/containerd/snapshots/overlay/plugin"
+)