Replace hook_node_delete() with hook_node_delete_multiple()

On my laptop with an SSD node_delete_multiple() can churn through about 1 node / second. Watching MySQL I see that the culprit is

Copying to tmp table SELECT DISTINCT SUBSTRING_INDEX(source, '/', 1) AS path FROM url_alias

If I edit path_delete() and comment out the call to drupal_clear_path_cache() performance jumps to about 50 nodes / second.

Currently node_delete_multiple() calls the delete hooks for each individual node, then removes data from node tables in a batch, and wraps the whole thing in a transaction in hopes of a moderate performance improvement.

What may work better is if we replaced hook_node_delete() with hook_node_delete_multiple() so that modules can act on nids in bulk.