Revert of [snapshot] full setup delegate should also be able to deserialize.

src/builtins/builtins.h

Index: src/builtins/builtins.h
diff --git a/src/builtins/builtins.h b/src/builtins/builtins.h
index 4ac899a2b6d609172a7e09be896e95ed25f3952a..9da714bc0ff783e0f126d25d1e5e6459205a93a2 100644
--- a/src/builtins/builtins.h
+++ b/src/builtins/builtins.h
@@ -90,12 +90,6 @@
 
   bool is_initialized() const { return initialized_; }
 
-  // Used by SetupIsolateDelegate and Deserializer.
-  void MarkInitialized() {
-    DCHECK(!initialized_);
-    initialized_ = true;
-  }
-
   MUST_USE_RESULT static MaybeHandle<Object> InvokeApiFunction(
       Isolate* isolate, bool is_construct, Handle<HeapObject> function,
       Handle<Object> receiver, int argc, Handle<Object> args[],
@@ -111,6 +105,11 @@
 
  private:
   Builtins();
+  // Used by SetupIsolateDelegate.
+  void MarkInitialized() {
+    DCHECK(!initialized_);
+    initialized_ = true;
+  }
 
   static void Generate_CallFunction(MacroAssembler* masm,
                                     ConvertReceiverMode mode,