Solution:
1. Download and activate the WPML Delete Jobs plugin.
2. Visit Tools → WPML Delete jobs
3. You will see a text area prefilled with job IDs, these are 50 suggested job IDs to delete first. These job IDs are the same that you will see in WPML → Translation Management → Jobs. You can uncheck some job IDs in case you don’t want to touch a few pages or posts.
4. Click Delete and wait. Once the content is deleted, you will see a new batch of 50 IDs to delete, and so on until there are no jobs for revision.
5. Finally click on Optimize _icl_translation_status table to reduce the size of icl_translation_status table.
6. Deactivate and remove the cleaning plugin.