Work items overwriting success links / get rid of success links

We should just rely on the actual files instead of the success links. This is complicated, so here are some notes:

• we should not block the event loop
• we need to hold the GC lock until all work items have "work item paths" because we delete or do not delete work items in the end
• we currently release the lock instantly after creating all work items
  • because of this we call a "dump state" early, after creating the items. that messes up all the time stamps and is generally bad.