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_eface.go

@@ -0,0 +1,59 @@
+package reflect2
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+type eface struct {
+	rtype unsafe.Pointer
+	data  unsafe.Pointer
+}
+
+func unpackEFace(obj interface{}) *eface {
+	return (*eface)(unsafe.Pointer(&obj))
+}
+
+func packEFace(rtype unsafe.Pointer, data unsafe.Pointer) interface{} {
+	var i interface{}
+	e := (*eface)(unsafe.Pointer(&i))
+	e.rtype = rtype
+	e.data = data
+	return i
+}
+
+type UnsafeEFaceType struct {
+	unsafeType
+}
+
+func newUnsafeEFaceType(cfg *frozenConfig, type1 reflect.Type) *UnsafeEFaceType {
+	return &UnsafeEFaceType{
+		unsafeType: *newUnsafeType(cfg, type1),
+	}
+}
+
+func (type2 *UnsafeEFaceType) 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 *UnsafeEFaceType) UnsafeIsNil(ptr unsafe.Pointer) bool {
+	if ptr == nil {
+		return true
+	}
+	return unpackEFace(*(*interface{})(ptr)).data == nil
+}
+
+func (type2 *UnsafeEFaceType) Indirect(obj interface{}) interface{} {
+	objEFace := unpackEFace(obj)
+	assertType("Type.Indirect argument 1", type2.ptrRType, objEFace.rtype)
+	return type2.UnsafeIndirect(objEFace.data)
+}
+
+func (type2 *UnsafeEFaceType) UnsafeIndirect(ptr unsafe.Pointer) interface{} {
+	return *(*interface{})(ptr)
+}