Revert of [serializer] print use count of external references.

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 8eca750f268727784f14142db40342640ba187c1..69bcf7d756ab369d0b9003bccd3f1161c33323f7 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -559,10 +559,6 @@
   }
   data->contexts_.Clear();
 
-#ifdef DEBUG
-  i::ExternalReferenceTable::instance(isolate)->ResetCount();
-#endif  // DEBUG
-
   i::StartupSerializer startup_serializer(isolate, function_code_handling);
   startup_serializer.SerializeStrongReferences();
 
@@ -576,13 +572,6 @@
   }
 
   startup_serializer.SerializeWeakReferencesAndDeferred();
-
-#ifdef DEBUG
-  if (i::FLAG_external_reference_stats) {
-    i::ExternalReferenceTable::instance(isolate)->PrintCount();
-  }
-#endif  // DEBUG
-
   i::SnapshotData startup_snapshot(&startup_serializer);
   StartupData result =
       i::Snapshot::CreateSnapshotBlob(&startup_snapshot, &context_snapshots);