Update tests to run also on macOS

pkg/systemstatsmonitor/cpu_collector_unix.go

@@ -1,3 +1,5 @@
+//go:build unix
+
 /*
 Copyright 2020 The Kubernetes Authors All rights reserved.
 

pkg/systemstatsmonitor/memory_collector_unix.go

@@ -1,3 +1,5 @@
+//go:build unix
+
 /*
 Copyright 2020 The Kubernetes Authors All rights reserved.
 

pkg/systemstatsmonitor/types/config_darwin.go

@@ -0,0 +1,24 @@
+/*
+Copyright 2023 The Kubernetes Authors All rights reserved.
+
+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 types
+
+const defaultProcPath = ""
+
+func (ssc *SystemStatsConfig) validateProcPath() error {
+	// not supported
+	return nil
+}