Reland "Fix memory leak caused by field type in descriptor array."

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 11294011a0557ee339603308c9adb65891e41b44..83b7da43889a4ba5aeca7e8d94297c7faf383369 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -3147,7 +3147,12 @@ int DescriptorArray::GetFieldIndex(int descriptor_number) {
 
 HeapType* DescriptorArray::GetFieldType(int descriptor_number) {
   DCHECK(GetDetails(descriptor_number).location() == kField);
-  return HeapType::cast(GetValue(descriptor_number));
+  Object* value = GetValue(descriptor_number);
+  if (value->IsWeakCell()) {
+    if (WeakCell::cast(value)->cleared()) return HeapType::None();
+    value = WeakCell::cast(value)->value();
+  }
+  return HeapType::cast(value);
 }