Constraints processing row_ins_check_foreign_constraint() was not
called because row_upd_check_references_constraints() didn't see
update as delete: node->is_delete was false.
Since MDEV-30378 we check for TRG_EVENT_DELETE to detect versioned
delete in ha_innobase::update_row().
Now we can use TRG_EVENT_DELETE to set upd_node->is_delete, so
constraints processing is triggered correctly.
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