Add in a concurrency aware subunit filter

A live filter for subunit stream that will let us display the
concurrency of the streams as we go.

* This includes the worker id as {#} at the beginning of the lines
* Dumps out stdout/stderr if they are found inline (makes for easier
  debug
* Dumps out pythonlogging on failures if found inline
* Prints skip reasons

Based on I1b529546e005f47aba56b451e1c0d8b0da09fca3, but because
that started as Robert's I couldn't un Abandon it.

Change-Id: Icc99b652e4e8ae85b73bb905a3b704447a63195f
Co-Authored-By: Robert Collins <rbtcollins@hp.com>
Merge "Add in a concurrency aware subunit filter"