S390: Fix S390 native build break due to printf format mismatch.

size_t defined as unsigned long on 31-bit s390.

R=jochen@chromium.org, jfb@chromium.org
TBR=ahaas@chromium.org,bmeurer@chromium.org,yangguo@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1889623002

Cr-Commit-Position: refs/heads/master@{#35457}

src/profiler/heap-snapshot-generator.cc

@@ -80,7 +80,7 @@ void HeapEntry::SetIndexedReference(HeapGraphEdge::Type type,
 void HeapEntry::Print(
     const char* prefix, const char* edge_name, int max_depth, int indent) {
   STATIC_ASSERT(sizeof(unsigned) == sizeof(id()));
-  base::OS::Print("%6" V8PRIuPTR " @%6u %*c %s%s: ", self_size(), id(), indent,
+  base::OS::Print("%6" PRIuS " @%6u %*c %s%s: ", self_size(), id(), indent,
                   ' ', prefix, edge_name);
   if (type() != kString) {
     base::OS::Print("%s %.40s\n", TypeAsString(), name_);