Make writemarker and hashnode functions availableto the integration tests bundle (#735)

Co-authored-by: Lz <imlangzi@qq.com>

Author: fabioDMFerreira

code/go/0chain.net/blobbercore/handler/handler_hashnode.go

@@ -1,6 +1,3 @@
-//go:build !integration_tests
-// +build !integration_tests
-
 package handler
 
 import (

code/go/0chain.net/blobbercore/handler/handler_writemarker.go

@@ -1,6 +1,3 @@
-//go:build !integration_tests
-// +build !integration_tests
-
 package handler
 
 import (