Pipeline runner iterates over all completed bundles during warm restart

[sgiavasis]

When restarting a run somewhere in the middle, the bundler will create the same bundle distribution as when the pipeline was first run, and will iterate over all of the completed bundles, confirming that they are complete, before getting to the one that needs to be resumed.

This should be changed so that the already completed participants are removed from consideration when putting together the bundles.