Fix OOM test for HOST ALL memspace

Add an access to each allocation so that pages are actually
allocated on the selected NUMA nodes.

Author: kswiecicki

test/memspaces/memspace_host_all.cpp

@@ -112,6 +112,9 @@ TEST_F(memspaceHostAllProviderTest, memoryPolicyOOM) {
             break;
         }
 
+        // Allocate the necessary pages, by accessing the memory at 'ptr'.
+        *static_cast<int *>(ptr) = 0xC0FFEE;
+
         UT_ASSERTne(ptr, nullptr);
         allocs.push_back(ptr);
     }