[wasm] reuse the first compiled module

src/snapshot/code-serializer.h

Index: src/snapshot/code-serializer.h
diff --git a/src/snapshot/code-serializer.h b/src/snapshot/code-serializer.h
index e82a7d5dd6d5787582263f850981e0988d3f8b22..b3c54d1c8479182e991990d5482d4cc7189032d5 100644
--- a/src/snapshot/code-serializer.h
+++ b/src/snapshot/code-serializer.h
@@ -36,6 +36,7 @@ class CodeSerializer : public Serializer {
     UNREACHABLE();
   }
 
+  virtual bool ElideObject(Object* obj) { return false; }
   void SerializeGeneric(HeapObject* heap_object, HowToCode how_to_code,
                         WhereToPoint where_to_point);
 
@@ -73,6 +74,8 @@ class WasmCompiledModuleSerializer : public CodeSerializer {
     }
   }
 
+  bool ElideObject(Object* obj) override { return obj->IsWeakCell(); };
+
  private:
   WasmCompiledModuleSerializer(Isolate* isolate, uint32_t source_hash)
       : CodeSerializer(isolate, source_hash) {}