Revert vendor directory to support old golang (GOPATH mode)

gomodule is still in progress to migrate for now, hence multus
team decide to keep vendor directory to support build without
gomodule.

vendor/golang.org/x/sys/unix/race.go

@@ -0,0 +1,30 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin,race linux,race freebsd,race
+
+package unix
+
+import (
+	"runtime"
+	"unsafe"
+)
+
+const raceenabled = true
+
+func raceAcquire(addr unsafe.Pointer) {
+	runtime.RaceAcquire(addr)
+}
+
+func raceReleaseMerge(addr unsafe.Pointer) {
+	runtime.RaceReleaseMerge(addr)
+}
+
+func raceReadRange(addr unsafe.Pointer, len int) {
+	runtime.RaceReadRange(addr, len)
+}
+
+func raceWriteRange(addr unsafe.Pointer, len int) {
+	runtime.RaceWriteRange(addr, len)
+}