tests: replace all dest ref files on upgrade (if possible).

tests: replace all dest ref files on upgrade (if possible).
Originally we were copying all source files in, but this caused
problems when (large) inputs were copied along with outputs.
Then we switched to just copying the standard files (m5stats.txt,
etc.) but that was missing things like the *.console files.
This fix should catch all the non-standard files too as long as
they are copied in manually once when the test is set up.
Also get a lot nicer about warning when files are ignored,
and warn when expected files are missing.
Those new Python sets sure are handy.

--HG--
extra : convert_revision : 55c046de124522499af74a471968677c020bbf38