Hacky fix for SlowSloppyElementsAccessor::Set

src/elements.cc

Index: src/elements.cc
diff --git a/src/elements.cc b/src/elements.cc
index e830d7c46500524ce32a8f0b213fc16214d5094d..8c1f300d7edeb77f2ad3aab6844abbe3042fd604 100644
--- a/src/elements.cc
+++ b/src/elements.cc
@@ -1488,7 +1488,22 @@ class SloppyArgumentsElementsAccessor
       context->set(context_entry, value);
     } else {
       FixedArray* arguments = FixedArray::cast(parameter_map->get(1));
-      ArgumentsAccessor::SetImpl(arguments, index, value);
+      SeededNumberDictionary* backing_store =
+          SeededNumberDictionary::cast(arguments);
+      int entry = backing_store->FindEntry(index);
+      DCHECK_NE(entry, SeededNumberDictionary::kNotFound);
+      Object* current_value = backing_store->ValueAt(entry);
+      if (current_value->IsAliasedArgumentsEntry()) {
+        DisallowHeapAllocation no_gc;
+        AliasedArgumentsEntry* alias =
+            AliasedArgumentsEntry::cast(current_value);
+        Context* context = Context::cast(parameter_map->get(0));
+        int context_entry = alias->aliased_context_slot();
+        DCHECK(!context->get(context_entry)->IsTheHole());
+        context->set(context_entry, value);
+      } else {
+        ArgumentsAccessor::SetImpl(arguments, index, value);
+      }
     }
   }