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

src/external-reference-table.h

Index: src/external-reference-table.h
diff --git a/src/external-reference-table.h b/src/external-reference-table.h
index 39910c0db8ad935cabead8ba8c76e9318d673a5f..fb671a86307d285903cb21f728c5629e0db0f279 100644
--- a/src/external-reference-table.h
+++ b/src/external-reference-table.h
@@ -23,24 +23,12 @@
   Address address(uint32_t i) { return refs_[i].address; }
   const char* name(uint32_t i) { return refs_[i].name; }
 
-#ifdef DEBUG
-  void increment_count(uint32_t i) { refs_[i].count++; }
-  int count(uint32_t i) { return refs_[i].count; }
-  void ResetCount();
-  void PrintCount();
-#endif  // DEBUG
-
-  static const char* ResolveSymbol(void* address);
-
   static const int kDeoptTableSerializeEntryCount = 64;
 
  private:
   struct ExternalReferenceEntry {
     Address address;
     const char* name;
-#ifdef DEBUG
-    int count;
-#endif  // DEBUG
   };
 
   explicit ExternalReferenceTable(Isolate* isolate);