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/github.com/modern-go/reflect2/unsafe_ptr.go

@@ -0,0 +1,46 @@
+package reflect2
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+type UnsafePtrType struct {
+	unsafeType
+}
+
+func newUnsafePtrType(cfg *frozenConfig, type1 reflect.Type) *UnsafePtrType {
+	return &UnsafePtrType{
+		unsafeType: *newUnsafeType(cfg, type1),
+	}
+}
+
+func (type2 *UnsafePtrType) IsNil(obj interface{}) bool {
+	if obj == nil {
+		return true
+	}
+	objEFace := unpackEFace(obj)
+	assertType("Type.IsNil argument 1", type2.ptrRType, objEFace.rtype)
+	return type2.UnsafeIsNil(objEFace.data)
+}
+
+func (type2 *UnsafePtrType) UnsafeIsNil(ptr unsafe.Pointer) bool {
+	if ptr == nil {
+		return true
+	}
+	return *(*unsafe.Pointer)(ptr) == nil
+}
+
+func (type2 *UnsafePtrType) LikePtr() bool {
+	return true
+}
+
+func (type2 *UnsafePtrType) Indirect(obj interface{}) interface{} {
+	objEFace := unpackEFace(obj)
+	assertType("Type.Indirect argument 1", type2.ptrRType, objEFace.rtype)
+	return type2.UnsafeIndirect(objEFace.data)
+}
+
+func (type2 *UnsafePtrType) UnsafeIndirect(ptr unsafe.Pointer) interface{} {
+	return packEFace(type2.rtype, *(*unsafe.Pointer)(ptr))
+}