Hide some runtime functions.

src/serialize.cc

Index: src/serialize.cc
diff --git a/src/serialize.cc b/src/serialize.cc
index 219761e2bfdcd635b1b88c438ee8608dcc1126cb..45bc8f22c7953cb62c1fb1d0b1f88790174b1f14 100644
--- a/src/serialize.cc
+++ b/src/serialize.cc
@@ -508,11 +508,12 @@ void ExternalReferenceTable::PopulateTable(Isolate* isolate) {
       UNCLASSIFIED,
       52,
       "cpu_features");
-  Add(ExternalReference(Runtime::kAllocateInNewSpace, isolate).address(),
+  Add(ExternalReference(Runtime::kHiddenAllocateInNewSpace, isolate).address(),
       UNCLASSIFIED,
       53,
       "Runtime::AllocateInNewSpace");
-  Add(ExternalReference(Runtime::kAllocateInTargetSpace, isolate).address(),
+  Add(ExternalReference(
+          Runtime::kHiddenAllocateInTargetSpace, isolate).address(),
       UNCLASSIFIED,
       54,
       "Runtime::AllocateInTargetSpace");