test: force-disable pmemcheck in obj_root test

src/test/obj_root/TEST1

 #!/usr/bin/env bash
 #
-# Copyright 2018, Intel Corporation
+# Copyright 2018-2019, Intel Corporation
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
@@ -40,6 +40,9 @@
 
 require_test_type long
 
+# the test takes too long under pmemcheck
+configure_valgrind pmemcheck force-disable
+
 setup
 
 # required free space is larger than file size, to be sure that the test