src: print MKSNAPSHOT debug logs to stderr

Author: joyeecheung

src/node_realm.cc

@@ -223,7 +223,7 @@ void Realm::PrintInfoForSnapshot() {
   fprintf(stderr, "BaseObjects of the Realm:\n");
   size_t i = 0;
   ForEachBaseObject([&](BaseObject* obj) {
-    std::cout << "#" << i++ << " " << obj << ": " << obj->MemoryInfoName()
+    std::cerr << "#" << i++ << " " << obj << ": " << obj->MemoryInfoName()
               << "\n";
   });
 

src/node_snapshotable.cc

@@ -1075,7 +1075,7 @@ ExitCode SnapshotBuilder::CreateSnapshot(SnapshotData* out,
 
       if (per_process::enabled_debug_list.enabled(DebugCategory::MKSNAPSHOT)) {
         env->ForEachRealm([](Realm* realm) { realm->PrintInfoForSnapshot(); });
-        printf("Environment = %p\n", env);
+        fprintf(stderr, "Environment = %p\n", env);
       }
 
       // Serialize the native states