[Piglit] recovering from aborted runs

[Brian Paul]

Hi Dylan,

I don't know when this changed, but when piglit runs now, it creates 
individual tests/NNNN.json files for each test.  Then at the end, it 
combines them into the results.json file.

If the piglit run is interrupted (host crash/freeze), I'm left with all 
those individual files and no results.json file.  Is there command I can 
run to generate the results.json file from the individual files?

-Brian