As a last resort try to allocate out of the smaller size size-class in

src/spaces.h

Index: src/spaces.h
diff --git a/src/spaces.h b/src/spaces.h
index 56be1406b6384eccc7335458729ff77c019f2c96..d964549e567201ace745c48cb99695b69921d4de 100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -1454,6 +1454,7 @@ class FreeListCategory {
   void Free(FreeListNode* node, int size_in_bytes);
 
   FreeListNode* PickNodeFromList(int *node_size);
+  FreeListNode* PickNodeFromList(int size_in_bytes, int *node_size);
 
   intptr_t EvictFreeListItemsInList(Page* p);
 
@@ -1820,11 +1821,6 @@ class PagedSpace : public Space {
     return area_size_;
   }
 
-  bool ConstantAllocationSize() {
-    return identity() == MAP_SPACE || identity() == CELL_SPACE ||
-        identity() == PROPERTY_CELL_SPACE;
-  }
-
  protected:
   FreeList* free_list() { return &free_list_; }