Checking `new_record?` when using upsert

I believe that `new_record?` will always be true when using `upsert` because `new_record?` basically does `id.value.nil?`. The `id.value` is only filled in when you pass in `@record` which doesn't happen on upserts.

I'll have to look more in to this, but we had an issue using `new_record?` with the upsert, and it seemed that it was always returning true no matter what.

Start by tracing how new_record? determines its result during an upsert, focusing on the id value and the @record path mentioned in the report. Reproduce the behavior and establish the expected result for both new and existing records; done means the behavior is corrected or clearly confirmed with regression coverage.

Written by the indexing model from the issue text.