Update survival statistics correctly in the Scavenger.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 4dea51050d3f1a37e21b81ae7ea9ec53ceb4d341..45e8be9ea62487969a5dc2f7cd7e9eb5513b129d 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -2037,6 +2037,9 @@ class ScavengingVisitor : public StaticVisitorBase {
         ASSERT(heap->AllowedToBeMigrated(object, OLD_POINTER_SPACE));
         allocation = heap->old_pointer_space()->AllocateRaw(allocation_size);
       }
+      heap->IncrementPromotedObjectsSize(object_size);
+    } else {
+      heap->IncrementSemiSpaceCopiedObjectSize(object_size);
     }
 
     HeapObject* target = HeapObject::cast(allocation.ToObjectChecked());
@@ -2050,7 +2053,6 @@ class ScavengingVisitor : public StaticVisitorBase {
     // buffer.
     *slot = target;
     MigrateObject(heap, object, target, object_size);
-    heap->IncrementSemiSpaceCopiedObjectSize(object_size);
     return;
   }