Reland "Merge cellspace into old pointer space"

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 8219f3ed2200af69a9e1bae3e97c179300f60b4f..64a05167218c7d4f2cd599e2ea07cec495f1d83b 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -5706,9 +5706,6 @@ inline bool ReceiverObjectNeedsWriteBarrier(HValue* object,
   while (object->IsInnerAllocatedObject()) {
     object = HInnerAllocatedObject::cast(object)->base_object();
   }
-  if (object->IsConstant() && HConstant::cast(object)->IsCell()) {
-    return false;
-  }
   if (object->IsConstant() &&
       HConstant::cast(object)->HasExternalReferenceValue()) {
     // Stores to external references require no write barriers