Added a second pipeline for more immediate jobs.

* The list of immediate job types is AssembleUploadChunks and PublishStashedFile.
* Also fixed regression where the -t param was ignored, though it's not very  useful.
* Tweaked locations of $foundjobs setting to be clearer and fix a very minor bug.
* Fixed the trapping to catch SIGINT for the overall loop and fixed the shell
  processes that spawn runJobs.php to actually kill all the children (not just the last).
* Also cleaned up the process count code to use `jobs -p`.

Change-Id: I28ae90fb77afb055a90d1efc318f20f4747aff3d
Merge "Added a second pipeline for more immediate jobs." into production