batches: remove CreateChangesetJobs calls from bulk_processor_test.go unit tests

Created by: LawnGnome

I don't think this is actually required, since the bulk processor doesn't try to load it from the database. Might be an option to save another database hit.

Originally posted by @mrnugget in https://github.com/sourcegraph/sourcegraph/pull/22908#discussion_r671192877