MIPS: Do the qNaN fixup at de-serialization time.

src/serialize.cc

Index: src/serialize.cc
diff --git a/src/serialize.cc b/src/serialize.cc
index c6f9971816eb31f3e591988c410dae6215b86a59..01d5f1c7bcb034efd6a4f95c1094a4502a0001ed 100644
--- a/src/serialize.cc
+++ b/src/serialize.cc
@@ -1444,8 +1444,6 @@ void Serializer::ObjectSerializer::Serialize() {
     sink_->PutSection(space, "NewPageSpace");
   }
 
-  if (object_->IsNaN()) Assembler::QuietNaN(object_);
-
   // Serialize the map (first word of the object).
   serializer_->SerializeObject(object_->map(), kPlain, kStartOfObject);