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

src/snapshot/snapshot.h

Index: src/snapshot/snapshot.h
diff --git a/src/snapshot/snapshot.h b/src/snapshot/snapshot.h
index 7d9082e6d21080cd13b7686720159aa20b2b3369..30dbd236ddac200ef688ed67686dcd06212dff30 100644
--- a/src/snapshot/snapshot.h
+++ b/src/snapshot/snapshot.h
@@ -62,6 +62,8 @@
       size_t context_index,
       v8::DeserializeEmbedderFieldsCallback embedder_fields_deserializer);
 
+  static bool HaveASnapshotToStartFrom(Isolate* isolate);
+
   static bool HasContextSnapshot(Isolate* isolate, size_t index);
 
   static bool EmbedsScript(Isolate* isolate);